Fast Open Shortest Path First (OSPF)

Area Commands

The following are OSPF area-wide commands that are configured in OSPF Router Configuration Mode. These configurations override any similar global-wide commands:

"area advertise-subnet"

"area filter"

"area nssa-translate-always"

"area nssa"

"area nssa-range"

"area priority"

"area range"

"area stub"

"area stubhost"

"area stubnetwork"

"area transmit-delay"

"area virtual-link"

Default Commands

The following OSPF default commands are configured in OSPF Router Configuration Mode:

"default-metric"

"default-nssa-metric"

Area Interface Commands

The following commands are configured in Area Interface Configuration Mode:

"traffic-eng administrative-weight"

"traffic-eng attribute-flags"

"traffic-eng bandwidth"

"ip ospf advertise-subnet"

Floating Interface Commands

The following commands are configured in Interface Configuration Mode:

"ip ospf allow-all"

"ip ospf cost"

"ip ospf passive-interface"

"ip ospf enable"

"ip ospf hello-interval"

"ip ospf neighbor"

"ip ospf network"

"ip ospf no-multicast"

"ip ospf priority"

"ip ospf traffic-eng administrative-weight"

"ip ospf traffic-eng attribute-flags"

"ip ospf traffic-eng bandwidth"

"ip ospf transmit-delay"

Querying Commands

"show ip ospf"

"show ip ospf border-routers"

"show ip ospf database"

"show ip ospf interface"

"show ip ospf neighbor"

"show ip ospf request-list"

"show ip ospf retransmission-list"

"show ip ospf summary-address"

"show ip ospf virtual-links"

router ospf

Name

router ospf - enters configuration mode for an instance in OSPF

Syntax

router ospf instance_id

no router ospf instance_id

Mode

Global Configuration

Parameters

instance_id - an integer from 1 to 4,294,967,294, inclusive, identifying the OSPF instance that you want to configure

Description

Use the router ospf command to enter OSPF Router Configuration mode for an OSPF instance. Once you are in OSPF Router Configuration mode, you can begin configuring a new OSPF instance or change an existing configuration.

Default

None. You must specify this command with an instance_id in order to configure OSPF.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example shows how to enter OSPF Router Configuration mode for OSPF instance 1.

(config)# router ospf 1

(config-router-ospf)#

advertise-subnet

Name

advertise-subnet - specifies whether OSPF will, when advertising point-to-point interfaces, advertise the network number and netmask instead of a host route to the remote IP

Syntax

advertise-subnet

no advertise-subnet

Mode

OSPF Router Configuration

Parameters

none

Description

The advertise-subnet command specifies whether OSPF will, when advertising point-to-point interfaces, advertise the network number and netmask of the point-to-point interface instead of a host route to the remote IP. Because the netmask is sometimes set improperly on point-to-point interfaces, this option disabled by default.

This command can be overridden at the area and interface levels.

Default

If advertise-subnet is not specified, it is the same as if the user had specified the following:
(config-router-ospf)# no advertise-subnet

Command History

NGC 2.2 - This command was introduced.

Examples

The following example turns the global advertise-subnet on, then turns it off for area 1.2.3.4.

(config)# router ospf 1

(config-router-ospf)# advertise-subnet

(config-router-ospf)# no area 1.2.3.4 advertise-subnet

(config-router-ospf)# exit

(config)#

See Also

"area advertise-subnet"

"ip ospf advertise-subnet"

authentication

Name

authentication - specifies the type of OSPF authentication used and any key values

Syntax

authentication [ [simple key] | [ md5 id_number md5_key
[(start-generate date_time) ||
(stop-generate date_time) || (start-accept date_time)
(stop-accept date_time)]? ] ]

no authentication [simple key | md5 id_number]

Mode

OSPF Router Configuration

Parameters

simple key - specifies simple (clear password) authentication. The value for key is specified as a one- to eight-character string.

md5 id_number md5_key [(start-generate date_time) || (stop-generate date_time) || (start-accept date_time) || (stop-accept date_time)] - specifies the authentication used for specifying md5 cryptographic authentication. The value for id_number is an integer with a value between 1 and 255, inclusive. The value for md5_key is a one- to sixteen-character string. The start and stop values must be in the format: YYYY-MM-DD.HH.MM. Each start and stop value is optional, and order is not important when specifying multiple commands.

Description

Authentication can help to guarantee that routing information is imported only from trusted routers. A variety of authentication schemes can be used, but a single scheme must be configured for each network. The use of different schemes enables some interfaces to use much stricter authentication than others. The two authentication schemes available are simple, and MD5.

The authentication command specifies the type of global authentication and key values used in OSPF. The negative form of this command removes authentication for the area. Authentication is used by OSPF to generate and verify the authentication field in the OSPF header. The global authentication is the default and can be overridden at the area command and interface levels.

When you want to keep certain routers from exchanging OSPF packets, use the simple form of authentication. The interfaces that the packets are to be sent on still need to be trusted, because the key will be placed in the packets and can be seen by anyone with access to the network.

When you do not trust other users of your network, use MD5 authentication. The system works by using shared secret keys. Because the keys are used to sign the packets with an MD5 checksum, they cannot be forged or tampered with. Because the keys are not included in the packet, snooping the key is not possible. Users of the network can still snoop the contents of packets, however, because the packets are not encrypted.

Advanced Routing Suite's MD5 authentication is compliant with the specification in OSPF RFC 2328. This specification uses the MD5 algorithm and an authentication key of up to 16 characters. RFC 2328 allows multiple MD5 keys per interface. Each key has associated time ranges.

Note: In order to turn off authentication, you must include the authentication type in the no form of the command. For example, if MD5 authentication was configured, then simply specifying no authentication will not work. In addition, you must specify the simple key when turning off simple authentication, and you must specify the MD5 id_number when turning off MD5 authentication.

Default

The default is for no authentication to be explicitly configured.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures simple authentication in OSPF instance 1.

(config)# router ospf 1

(config-router-ospf)# authentication simple abc

(config-router-ospf)# exit

(config)#

Example 2

The following example configures md5 authentication for OSPF instance 2. The ID for this md5 configuration is 1, and the key is configured as "bar".

(config)# router ospf 2

(config-router-ospf)# authentication md5 1 bar

(config-router-ospf)# exit

(config)#

Example 3

The following example turns off the MD5 authentication that was configured in Example 2. Note that specifying the MD5 key is not required, but specifying the MD5 ID is.

(config)# router ospf 2

(config-router-ospf)# no authentication md5 1

(config-router-ospf)# exit

(config)#

Example 4

The following example configures md5 authentication for OSPF instance 3. The md5 authentication is configured with a start-generate time set to January 02, 2004 at 21:30 hours, a stop-generate time set to January 02, 2004 at 21:45 hours, a start-accept time set to January 02, 2004 at 21:00 hours, and a stop-accept time set to January 02, 2004 at 22:00 hours.

(config)# router ospf 3

(config-router-ospf)# authentication md5 2 md5
start-generate 2004-01-02.21.30 stop-generate
2004-01-02.21.45 start-accept 2004-01-02.21.00
stop-accept 2004-01-02.22.00

(config-router-ospf)# exit

(config)#

See Also

compatible rfc1583

Name

compatible rfc1583 - specifies to run in RFC 1583 mode instead of RFC 2328 mode

Syntax

compatible rfc1583

no compatible rfc1583

Mode

OSPF Router Configuration

Parameters

none

Description

The compatible rfc1583 command specifies to run in RFC 1583 mode instead of RFC 2328 mode. Do not specify this command if all the routers using an OSPF implementation in your domain are based on RFC 2328 or later. This option should be specified the same way on all routers in the domain. If any of the routers do not have this option, you should always enable this. When disabled, the preference rules for best route election are changed to eliminate certain kinds of possible routing loops.

The negative of this command, no compatible rfc1583, removes the requirement to run in RFC 1583 mode and reverts to RFC 2328 mode.

Default

If compatible rfc1583 is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# compatible rfc1583

Command History

NGC 2.2 - This command was introduced.

Examples

The following example disables RFC 1583 mode in for instance 1 of OSPF.

(config)# router ospf 1

(config-router-ospf)# no compatible rfc1583

(config-router-ospf)# exit

(config)#

dead-interval

Name

dead-interval - specifies the number of seconds that can elapse without receiving a router’s hello packets before the router’s neighbors will declare it down

Syntax

dead-interval time-seconds

no dead-interval time-seconds?

Mode

OSPF Router Configuration

Parameters

time-seconds - an integer between 1 and 65535, inclusive, specifying a time in seconds

Description

Use the global dead-interval command to specify the number of seconds that may elapse without receiving a router’s hello packets before the router’s neighbors will declare it down. This value can be overridden at the area and interface levels. A general rule is for this value to equal three times the HELLO interval. Do not set this value to be less than the HELLO interval or convergence will not occur.

The negative form of this command, no dead-interval, removes the configured value and returns this to its default value of 40 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If dead-interval is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# dead-interval 40

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a global dead-interval value of 30. This value is then overridden in area 1.2.3.4 to be 25.

(config)# router ospf 1

(config-router-ospf)# dead-interval 30

(config-router-ospf)# area 1.2.3.4 dead-interval 25

(config-router-ospf)# exit

(config)#

See Also

distance

Name

distance - specifies how active routes that are learned from OSPF internal reachability will be selected, compared to other protocols

Syntax

distance int_value

no distance int_value?

Mode

OSPF Router Configuration

Parameters

int_value - the Advanced Routing Suite preference for internal routes. This can be an integer from 1 to 255, inclusive.

Description

The distance command specifies how active routes that are learned from the OSPF internal reachability (compared to other protocols) will be selected. When a route has been learned from more than one protocol, the active route will be selected from the protocol with the lowest distance. Each protocol has a default distance in this selection.

The negative form of this command, no distance, removes the configured value and returns this to its default value of 10.

Default

If distance is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# distance 10

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the default distance for internal routes to be 100.

(config)# router ospf 1

(config-router-ospf)# distance 100

(config-router-ospf)# exit

(config)#

enable

Name

enable - enables an OSPF instance

Syntax

enable

no enable

Mode

OSPF Router Configuration

Parameters

none

Description

The enable command enables the state for an OSPF instance. The negative form of this command, no enable, disables the instance. If an enabled instance is disabled, then it is stopped, and all running state is deleted. All configuration state, however, is preserved. If a disabled instance is enabled, it will start running again with its preserved configuration state.

Default

If enable is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# enable

Command History

NGC 2.2 - This command was introduced.

Examples

The following example disables OSPF instance 3.

(config)# router ospf 3

(config-router-ospf)# no enable

(config-router-ospf)# exit

(config)#

enable-te

Name

enable-te - causes OSPF to originate Traffic Engineering (TE) information in Opaque LSAs

Syntax

enable-te

no enable-te

Mode

Global Configuration

Parameters

none

Description

Use the enable-te command to cause OSPF to originate TE information in Opaque LSA for all running OSPF interfaces. This information does not affect normal OSPF routing and provides extra parameters for links and routers in the topology, such as available bandwidth.

Default

If enable-te is not specified, it is the same as if the user had specified:

(config)# no enable-te

Command History

NGC 2.2 - This command was introduced.

Examples

The following example enables Traffic Engineering LSAs for OSPF router instance 1.

(config)# router ospf 1

(config-router-ospf)# enable-te

(config-router-ospf)# exit

(config)#

hello-interval

Name

hello-interval - specifies the time in seconds between hello packets that the other router sends on an interface

Syntax

hello-interval time-seconds

no hello-interval time-seconds?

Mode

OSPF Router Configuration

Parameters

time-seconds - the length of time in seconds, between 1 and 65535, inclusive specified as an integer

Description

The hello-interval command specifies the time in seconds between hello packets that the router send on the interface. This option is specified here at the global level. It can be overridden in the area and interface levels. (See "area hello-interval" and "ip ospf hello-interval".)

The negative form of this command, no hello-interval, removes the configured value and returns this to its default value of 10 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If hello-interval is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# hello-interval 10

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a global hello interval of 15 seconds. This is then overridden in the area statement, where it is configured to be 5 seconds.

(config)# router ospf 1

(config-router-ospf)# hello-interval 15

(config-router-ospf)# area 1.2.3.4 hello-interval 5

(config-router-ospf)# exit

(config)#

See Also

"ip ospf hello-interval"

igp-shortcut

Name

igp-shortcut - enables the IGP shortcut feature for OSPF

Syntax

igp-shortcut

no igp-shortcut

Mode

OSPF Router Configuration

Parameters

none

Description

The igp-shortcut command enables the IGP Shortcut feature for OSPF. When configured, OSPF will consider MPLS tunnels as uni-directional, directly connected, point-to-point links. To disable this feature, use the negative form of the command.

Default

If the igp-shortcut command is not explicitly configured, it is as if the user had configured the following:

(config-router-ospf)# no igp-shortcut

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following command enables the IGP Shortcut feature for OSPF instance 1.

(config)# router ospf 1

(config-router-ospf)# igp-shortcut

(config-router-ospf)# exit

(config)#

Example 2

The following command disables the IGP Shortcut feature for OSPF instance 1.

(config)# router ospf 1

(config-router-ospf)# no igp-shortcut

(config-router-ospf)# exit

(config)#

inherit-metric

Name

inherit-metric - configures an OSPF ASE route to inherit the metric of the external route when no metric is specified on the export policy

Syntax

inherit-metric

no inherit-metric

Mode

OSPF Router Configuration

Parameters

none

Description

Use the inherit-metric command to allow an OSPF ASE route to inherit the metric of the external route when no metric is specified on the export policy. This feature maintains compatibility with all the current export functions. A metric specified on the export policy takes precedence. The metric specified in the defaults section ("default-metric") will be used if this command is not specified.

Default

If inherit-metric is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# no inherit-metric

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures ASE routes exported into OSPF to inherit the metric of the external route.

(config)# router ospf 1

(config-router-ospf)# inherit-metric

(config-router-ospf)# exit

(config)#

monitor-auth-key

Name

monitor-auth-key - sets an authentication key when using the OSPF Monitor tool

Syntax

monitor-auth-key string

no monitor-auth-key string

Mode

OSPF Router Configuration

Parameters

string - a string of up to eight characters

Description

Use the monitor-auth-key command to set an authentication key when using the OSPF Monitor tool. The negative form of this command, no monitor-auth-key, removes the password previously defined by this command and reverts to the default of no password.

Default

If monitor-auth-key is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# no monitor-auth-key

Command History

NGC 2.2 - This command was introduced.

Examples

The following example sets the monitor-auth-key authentication to "abc-auth".

(config)# router ospf 2

(config-router-ospf)# monitor-auth-key abc-auth

(config-router-ospf)# exit

(config)#

See Also

"Chapter 4 OSPF Monitor (ospfmon)" in Operating Advanced Routing Suite

multicast-rib

Name

multicast-rib - specifies the RIB in which OSPF internal routes are installed

Syntax

multicast-rib

no multicast-rib

Mode

OSPF Router Configuration

Parameters

none

Description

The multicast-rib command specifies the RIB into which OSPF internal routes are installed. The unicast RIB is required and is the default. In code bases that support extended RIBs, OSPF routes can be installed in the multicast RIB.

This command has no effect on self-originated ASE or NSSA routes because they are exported from another protocol. The negative form of this command, no multicast-rib reverts this back to its default of no multicast-rib.

Default

If multicast-rib is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# no multicast-rib

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures OSPF routes to be installed in the unicast and multicast RIBs.

(config)# router ospf 1

(config-router-ospf)# multicast-rib

(config-router-ospf)# exit

(config)#

network area

Name

network area - defines the interfaces on which OSPF will run, and defines the area ID for those interfaces

Syntax

network ip_address wildcard-mask area area_id

no network ip_address wildcard-mask area area_id

Mode

OSPF Router Configuration

Parameters

ip_address - a valid IP address

wildcard-mask - IP-address-type mask that includes "don’t care" bits

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone. If you intend to associate areas with IP subnets, you can specify a subnet address for this value.

Description

Use the network area command to specify interfaces on which OSPF runs and to define the area ID for those interfaces. Use the negative form of this command, no network area, to disable OSPF routing for any specified interfaces.

Default

This command is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example defines network 192.168.10.5 0.0.0.255 in area 1.2.3.4

(config)# router ospf 1

(config-router-ospf)# network 192.168.10.5 0.0.0.255 area 1.2.3.4

(config-router-ospf)# exit

(config)#

Example 2

The following example disables OSPF routing on interface 102.168.10.10 in area 1.2.3.4.

(config)# router ospf 1

(config-router-ospf)# no network 192.168.10.10 0.0.0.0 area 1.2.3.4

(config-router-ospf)# exit

(config)#

nssa-inherit-metric

Name

nssa-inherit-metric - allows an OSPF NSSA route to inherit the metric of the external route when no metric is specified on the export policy

Syntax

nssa-inherit-metric

no nssa-inherit-metric

Mode

OSPF Router Configuration

Parameters

none

Description

The nssa-inherit-metric command allows an OSPF NSSA route to inherit the metric of the external route when no metric is specified on the export policy. This feature maintains compatibility with all the current export functions. A metric specified on the export policy will take precedence.

Default

If nssa-inherit-metric is not specified, it is the same as if the user had specified the following:

(config)# no nssa-inherit-metric

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures NSSA routes exported into OSPF to inherit the metric of the external route.

(config)# router ospf 1

(config-router-ospf)# nssa-inherit-metric

(config-router-ospf)# exit

(config)#

nssa-stability-interval

Name

nssa-stability-interval - sets the length of time in seconds that an NSSA translator will continue to translate after losing the translator election

Syntax

nssa-stability-interval time-seconds

no nssa-stability-interval time-seconds?

Mode

OSPF Router Configuration

Parameters

time-seconds - an integer between 1 and 65535, inclusive, specifying an amount of time in seconds

Description

An NSSA ABR can translate Type 7 LSAs into Type 5 LSAs. A translator election is run to determine which one ABR for a given NSSA will translate. When an ABR was a translator and loses this election, it will cease translating after the amount of time specified by time-seconds. This allows the newly translated Type 5 LSAs from the new translator to be flooded throughout the domain before the currently translated Type 5 LSAs from this translator are flushed and the Type 5 LSAs resulting from direct translation are allowed to age out.

Default

If nssa-stability-interval is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# nssa-stability-interval 40

Command History

NGC 2.2 - This command was introduced.

Examples

The following example sets the NSSA stability interval to 10 seconds.

(config)# router ospf 1

(config-router-ospf)# nssa-stability-interval 10

(config-router-ospf)# exit

(config)#

poll-interval

Name

poll-interval - specifies the length of time, in seconds, between OSPF packets that the router send before adjacency is established with a neighbor

Syntax

poll-interval time-seconds

no poll-interval time-seconds?

Mode

OSPF Router Configuration

Parameters

time-seconds - the length of time in seconds, between 1 and 65535, inclusive specified as an integer

Description

The poll-interval command specifies the length of time, in seconds, between OSPF packets that the router sends before an adjacency is established with a neighbor. Utilizing this command reduces network overhead in cases where a router may have a neighbor on a given interface at the expense of initial convergence time.

This value is configured here at the global level and can be overridden at the area and interface levels.

The negative form of this command, no poll-interval, removes the configured time-seconds value and returns this to its default value of 120 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If poll-interval is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# poll-interval 120

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a global poll interval of 100 seconds. This value is overridden in interface fxp1, where it is configured to be 110 seconds.

(config)# router ospf 1

(config-router-ospf)# poll-interval 100

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf poll-interval 110

(config-if)# exit

(config)#

See Also

priority

Name

priority - specifies the priority for becoming the designated router (DR)

Syntax

priority level

no priority level?

Mode

OSPF Router Configuration

Parameters

level - a priority number between 0 and 255, inclusive, for becoming a DR

Description

The priority command specifies a number between 0 and 255 that configures the priority for becoming the DR. When more than one router attached to a network attempts to become the DR, the one with the highest priority wins. If the competing routes have the same priority, the one with the highest router ID becomes the DR. The router coming in second in the election becomes the backup DR. A router with a router priority set to 0 is ineligible to become the DR.

This value is specified here at the global level and can be overridden at the area and interface levels ("area priority" and "ip ospf priority"). The negative form of this command, no priority, removes the configured value and returns this to its default value of 0. Note: Specifying a value for level in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If priority is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# priority 1

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a global priority of 10. This value is then overridden in area 1.2.3.4, where it is configured to be 15.

(config)# router ospf 1

(config-router-ospf)# priority 10

(config-router-ospf)# area 1.2.3.4 priority 15

(config-router-ospf)# exit

(config)#

See Also

"area priority"

"ip ospf priority"

redistribute

Name

redistribute - specifies routes to export to OSPF

Syntax

redistribute protocol [route-map name]? {0,9}

no redistribute protocol [route-map name]?

Mode

OSPF Router Configuration

Parameters

protocol - the protocol name whose routes you want to redistribute to the current protocol being configured. Valid protocols are aggregate, bgp, direct, isis, kernel, ospf, ospf-ase, rip, and static.

route-map name - the name of a route map to apply to these routes. Specifying this is optional.

{0,9} - although this command can be given multiple times, it can only be given once for each of the nine configurable protocols. In other words, if a redistribute command is given for a protocol and route map, and then given again for the same protocol with a different route map, the second configuration overrides the first.

Description

Use the redistribute command to specify routes to export into OSPF. This command causes routes from the specified protocol to be considered for redistribution into the current protocol. Additionally, if a route map is specified, then routes from the specified protocol that match the named route map will be considered for redistribution into the current protocol. If the referenced route map has not yet been configured, then an empty route map is created with the specified name.

Note: Configuring this away from its default removes the implicitly configured default. You will have to go back and specify to redistribute OSPF and direct routes after the first redistribute configuration in order to export those routes.

Default

The default is to redistribute OSPF and the direct routes associated with the interfaces on which OSPF is running. Note that this is an implicit default that is wiped away with the first redistribute configuration.

Example

Example 1

In the following example OSPF instance 2 is configured to redistribute all BGP and RIP routes.

(config)# router ospf 2

(config-router-ospf)# redistribute bgp

(config-router-ospf)# redistribute rip

(config-router-ospf)# exit

(config)#

Example 2

The following example configures a community set, "set1", that permits AS:num 101:102. It then configures an extended community set "ext-set1", that permits Route Target AS:num 201:202.

(config)# ip community-set set1 permit 101:102

(config)# ip extcommunity-set ext-set1 permit rt 201:202

The two are then added to a community list, called "commlist1".

(config)# ip community-list commlist1 permit set1

(config)# ip community-list commlist1 permit ext-set1

The community list is then applied to a route map called "match-commlist1". If the route map matches BGP Community list "commlist1", then the metric for routes will be set to 20.

(config)# route-map match-commlist1

(config-route-map)# match community commlist1

(config-route-map)# set metric 20

(config-route-map)# exit

(config)#

Finally, the route map ("match-commlist1") is applied to BGP routes and exported into instance 1 of OSPF.

(config)# router ospf 1

(config-router-ospf)# redistribute bgp route-map match-commlist1

(config-router-ospf)# exit

(config)#

Example 3

In the following example, route map "abc" is configured with the following match criteria:

If a route matches interface "fxp1" and a pre-configured BGP Community labeled "bgpcomm1", then communities specified in community "com-set-1" will be added to the route, communities specified in community labeled "com-set-2" will be deleted from the route, and the metric of the route will be set to 50.

(config)# route-map abc

(config-route-map)# match interface fxp1

(config-route-map)# match community-set bgpcomm1

(config-route-map)# set community-set com-set-1 additive

(config-route-map)# set community-set com-set-2 delete

(config-route-map)# set metric 50

(config-route-map)# exit

(config)#

This route map is then applied to static routes and exported into OSPF instance 2.

(config)# router ospf 2

(config-router-ospf)# redistribute static route-map abc

(config-router-ospf)# exit

redistribute-nssa

Name

redistribute-nssa - specifies routes to export to OSPF NSSA in an OSPF instance

Syntax

redistribute-nssa protocol [route-map name]? {0,9}

no redistribute-nssa protocol [route-map name]?

Mode

OSPF Router Configuration

Parameters

protocol - the protocol name whose routes you want to redistribute to the current protocol being configured. Valid protocols are aggregate, bgp, direct, kernel, isis, ospf, ospf-ase, rip, and static.

route-map name - the name of a route map to apply to these routes. Specifying this is optional.

Description

Use the redistribute-nssa command to specify routes to export into all NSSA areas in the current OSPF instance. This command causes routes from the specified protocol to be considered for redistribution into OSPF-NSSA. Additionally, if a route map is specified, then routes from the specified protocol that match the named route map will be considered for redistribution into OSPF-NSSA.

If the referenced route map has not yet been configured, then an empty route map is created with the specified name.

Default

The default is that OSPF does not redistribute any routes into NSSA.

Command History

NGC 2.2 - This command was introduced.

Examples

In the following example, a route map "abc" is configured to match all IPv4 prefixes (configured in prefix list "pl1"), to set the exported metric to 1, and to set the NSSA Propagate (P) bit.

(config)# ip prefix-list pl1 seq 1 permit 0.0.0.0/0 le 32

(config)# route-map abc

(config-route-map)# match ip address prefix-list pl1

(config-route-map)# set metric 1

(config-route-map)# set propagate

(config-route-map)# exit

(config)#

This route map is then applied to static routes and exported into OSPF NSSA.

(config)# router ospf 1

(config-router-ospf)# redistribute-nssa static route-map abc

(config-router-ospf)# exit

(config)#

require-vbit

Name

require-vbit - instructs the spf code to require that the vbit be set in the router LSAs of routers that are the end points of virtual links

Syntax

require-vbit

no require-vbit

Mode

OSPF Router Configuration

Parameters

none

Description

Specifying this command instructs the SPF code to require that the vbit be set in the router LSAs of routers that are the end points of virtual links. When this command is not specified, the vbit can be clear, and the virtual link will still be considered.

This command exists to work around a bug in some OSPF implementations.

Default

If require-vbit is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# no require-vbit

Command History

NGC 2.2 - This command was introduced.

Examples

The following example turns require-vbit on.

(config)# router ospf 1

(config-router-ospf)# require-vbit

(config-router-ospf)# exit

(config)#

restart-allow-changes

Name

restart-allow-changes - specifies whether changes in the network will cause any helper attempts to fail

Syntax

restart-allow-changes

no restart-allow-changes

Mode

OSPF Router Configuration

Parameters

none

Description

The restart-allow-changes command specifies whether a change in the network (for example, something that causes an SPF) will cause any helper attempts to fail. This command can be given for multiple instances.

Turning this command on configures the OSPF instance to cancel helper mode on all neighbors currently attempting a restart (either Graceful or Signaled) when a topology change occurs.

The negative form of this command, no restart-allow-changes configures the restart helper mode to ignore topology change. Note that this can cause black holes to occur in the network.

Default

If restart-allow-changes is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# no restart-allow-changes

Command History

NGC 2.3 - This command was introduced.

Examples

The following example turns the allow changes helper flag on.

(config)# router ospf 1

(config-router-ospf)# restart-allow-changes

(config-router-ospf)# exit

restart-enable

Name

restart-enable - specifies to attempt a restart after the next startup

Syntax

restart-enable

no restart-enable

Mode

OSPF Router Configuration

Parameters

none

Description

This command configures the restart ability for an OSPF instance. If the restart-enable command is configured for an instance when OSPF starts, and/or if Advanced Routing Suite is restarted with the -r flag (see "The Command-line Options" in Operating Advanced Routing Suite), then OSPF will perform restart operations.

Because of the nature of the CLI, this command must be given during a "conf file replace" in order for it to apply to the current startup attempt. The reason is that all OSPF configuration must be in place before any of the configuration is committed. This can only be guaranteed with a conf file replace.

Notes:

A reconfiguration will not result in an attempted restart. Only occurrences that force the instance to be deleted and re-created will result in a restart.
This command overrides the -r flag given during a restart. For example, if no restart-enable is configured for an instance, and then Advanced Routing Suite is restarted with the -r flag, restarts will not take place.

Default

If the restart-enable command is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# no restart-enable

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures OSPF to perform restart operations.

(config)# router ospf 1

(config-router-ospf)# restart-enable

(config-router-ospf)# exit

(config)#

restart-max-sync-time

Name

restart-max-sync-time - configures the grace period in seconds for an unplanned restart attempt, for an OSPF instance

Syntax

restart-max-sync-time time-seconds

no restart-max-sync-time time-seconds?

Mode

OSPF Router Configuration

Parameters

time-seconds - an integer from 1 to 65535, inclusive.

Description

The restart-max-sync-time command specifies the number of seconds that elapse before a restart attempt will time out and fail. This command can configured for multiple instances. For graceful restart, this value represents the grace period. For signaled restart, if all adjacencies are not restored by this number of seconds after the restart attempt begins, then the attempt will fail.

Note: Either the "restart-enable" command must be configured as "on" or Advanced Routing Suite must be restarted with the -r flag (see "The Command-line Options" in Operating Advanced Routing Suite) in order for this command to take effect.

The negative form of this command, no restart-max-sync-time, removes the configured time-seconds value. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If restart-max-sync-time is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# restart-max-sync-time 40

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures the period for a restart to be 30 seconds.

(config)# router ospf 1

(config-router-ospf)# restart-enable

(config-router-ospf)# restart-max-sync-time 30

(config-router-ospf)# exit

See Also

"restart-enable"

restart-type

Name

restart-type - specifies whether the type of future restarts will be graceful or signaled

Syntax

restart-type [graceful | signaled]

no restart-type [graceful | signaled]?

Mode

OSPF Router Configuration

Parameters

graceful | signaled - specifies either graceful or signaled restart

Description

The restart-type command specifies the type of restart that will be attempted for future restarts. This command can be given for multiple instances. For example, one instance can perform a graceful restart and one instance can perform a signaled restart, each at the same time.

Default

If the restart-type command is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# restart-type graceful

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures a restart type of signaled for OSPF instance 3.

(config)# router ospf 3

(config-router-ospf)# restart-enable

(config-router-ospf)# restart-type signaled

(config-router-ospf)# exit

(config)#

See Also

"restart-enable"

retransmit-interval

Name

retransmit-interval - specifies the number of seconds between link state advertisement (LSA) retransmissions for adjacencies

Syntax

retransmit-interval time-seconds

no retransmit-interval time-seconds?

Mode

OSPF Router Configuration

Parameters

time-seconds - the length of time in seconds, between 1 and 65535, inclusive specified as an integer

Description

The retransmit-interval command sets the default for the number of seconds between LSA retransmissions for adjacencies. If a Link State Protocol (LSP) is not acknowledged within the number of seconds specified here, it is re-sent.

This command is specified here at the global level and can be overridden in the area and interface levels ("area retransmit-interval" and "ip ospf retransmit-interval").

The negative form of this command, no retransmit-interval, removes the configured retransmit value and returns this to its default value of 5 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If retransmit-interval is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# retransmit-interval 5

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the global retransmit interval to be 10 seconds. This value is then overridden in area 1.2.3.4, where it is configured to be 15 seconds.

(config)# router ospf 1

(config-router-ospf)# retransmit-interval 10

(config-router-ospf)# area 1.2.3.4 retransmit-interval 15

(config-router-ospf)# exit

(config)#

See Also

"ip ospf advertise-subnet"

router-id

Name

router-id - sets the OSPF 32-bit router ID for the specified instance

Syntax

router-id rid_value

no router-id rid_value

Mode

OSPF Router Configuration

Parameters

rid_value - a 32-bit address in dotted-quad notation

Description

The router-id command sets the OSPF 32-bit router ID for the specified instance. If the Router ID is not specified, then the instance uses the global default router ID. The negative form of this command, no router-id, removes the configured router ID and returns this to its default value specified by the globally defined Router ID.

Default

If router-id is not specified, the instance uses the globally specified Router ID. If that is not specified, then the highest IP address will be used.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the OSPF router ID to be 4.3.2.1.

(config)# router ospf 1

(config-router-ospf)# router-id 4.3.2.1

(config-router-ospf)# exit

(config)#

timers spf

Name

timers spf - specifies the minimum time between when OSPF receives a topology change and when it starts the SPF computation

Syntax

timers spf time-seconds

no timers spf time-seconds?

Mode

OSPF Router Configuration

Parameters

time-seconds - the minimum interval between SPF calculations, specified as an integer between 1 and 65535, inclusive

Description

Use the timers spf command to specify the minimum time between when OSPF receives a topology change and when it starts the SPF computation. The negative form of this command, no timers spf, removes the configured time value and returns this to its default value of 5.

Default

If timers spf is not specified, it is the same as if the user had specified the following:

(config)# timers spf 5

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the SPF timer interval to be 15.

(config)# router ospf 1

(config-router-ospf)# timers spf 15

(config-router-ospf)# exit

(config)#

trace file

Name

trace file - specifies the file to receive tracing information, the size of the file, whether to overwrite existing files, and the maximum number of files allowed

Syntax

trace file file_name [ no-timestamp || overwrite]?

no trace file file_name [no-timestamp || overwrite]?

Mode

OSPF Router Configuration

Parameters

file_name - specifies the name of the file to receive the tracing information. Note that the file name is not specified in quotes.

no-timestamp - specifies that a timestamp should not be prepended to all trace lines

overwrite - specifies to begin tracing by appending or truncating an existing file

Description

The trace file command is associated with each protocol, so that information pertaining to a single protocol can be written to its own file. For OSPF, the trace file command in OSPF Router Configuration Mode specifies a file for tracing of all OSPF events. The negative form of this command disables this tracing. The specific events that are traced are controlled by the trace flag command.

The no-timestamp option disables the pre-pending of a timestamp to all lines written to the trace file. The default is to prepend a timestamp to all lines written to a trace file.

The overwrite option specifies whether to start tracing by truncating or appending to an existing file.

Note: These options are not cumulative across multiple commands. Consider the following example:

(config-router-ospf)# trace file /var/log/ospf.log
no-timestamp

(config-router-ospf)# trace file /var/log/ospf.log

The option given in the second command completely replaces that given in the first.

Default

OSPF tracing is turned off by default.

Command History

NGC 2.2 - This command was introduced.

Examples

In the following example, OSPF tracing is written to the file "/var/tmp/ospf.log". No timestamp will display at the beginning of the trace lines.

(config)# router ospf 1

(config-router-ospf)# trace file /var/tmp/ospf.log no-timestamp

trace flag

Name

trace flag - specifies OSPF-specific tracing options as well as options that are common across all protocols

Syntax

Mode

OSPF Router Configuration

Parameters

Flags common to all protocols:

[ route | normal | state | policy | task | timer | all ] - These tracing flags are common to all protocols. They cannot be associated with a send, receive, or send-receive action item. Similarly, you cannot specify to show detailed information when tracing these flags. These flags are defined as follows:

route - trace routing table changes for routes installed by this protocol or peer
normal - trace normal protocol occurrences. Note: Abnormal protocol occurrences are always traced.
state - trace state machine transition in the protocol
policy - trace the application of protocol and user-specified policy to routes being imported or exported
task - trace system interface and processing associated with this protocol
timer - trace timer usage by this protocol
all - turns on all trace flags

SPF-specific flags that do not allow associated actions:

ospf-state - trace OSPF state change information
drelect - trace the Designated Router operations
db - trace the link-state database operations
spf - trace the Shortest Path First (SPF) calculations
flood - trace the flooding procedure
debug - trace OSPF at the debugging level of detail

SPF-specific flags that allow associated actions:

[ packets | hello | dd | lsr | lsu | lsa ] - These OSPF-specific flags can be associated with the send, receive, or send-receive action items. These flags are defined as follows:

packets - trace all OSPF link-state packets
hello - trace OSPF hello packets, which are used to determine neighbor reachability
dd - trace OSPF Database Description (DD) packets, which are used in synchronizing OSPF databases
lsr - trace OSPF link-state request packets, which are used in synchronizing OSPF databases
lsu - trace OSPF link-state update packets, which are used in synchronizing OSPF databases
lsa - trace OSPF link-state acknowledgement packets, which are used in synchronizing OSPF databases

[ send | receive | send-receive ]? - optionally specify whether to limit the tracing to packets sent, received, or both

[detail?] - optionally specify to use a more verbose format when displaying information about the contents of packets instead of one or two lines

Description

Use the trace flag command to specify tracing flags for OSPF tracing. Each flag must reside on its own configuration line. For example, you cannot specify to trace both task and policy packets in the same command.

Default

The default is for no flags to be explicitly configured.

Command History

NGC 2.2 - This command was introduced.

Examples

In the following example, trace flags specify that both the sent and received link state request and hello messages are traced in detail. This tracing information will be written to the file /var/tmp/ospf.log.

(config)# router ospf 1

(config-router-ospf)# trace file /var/tmp/ospf.log

(config-router-ospf)# trace flag lsr send-receive detail

(config-router-ospf)# trace flag hello send-receive detail

transmit-delay

Name

transmit-delay - specifies the time in seconds required to transmit a link stat update

Syntax

transmit-delay time-seconds

no transmit-delay time-seconds?

Mode

OSPF Router Configuration

Parameters

time-seconds - the length of time in seconds, between 1 and 65535, inclusive specified as an integer

Description

The transmit-delay command sets the estimated number of seconds required to transmit a link state update. This command takes into account transmission and propagation delays and must be greater than 0. The transmit delay is specified here at the global level. It can be overridden at the area and interface levels ("area transmit-delay" and "ip ospf transmit-delay") as well as within a virtual link ("area virtual-link").

The negative form of this command, no transmit-delay, removes the configured time-seconds value and returns this to its default value of 1. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If transmit-delay is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# transmit-delay 1

Example

The following example configures a global transmit delay of 5 seconds. This value is then overridden in area 1.2.3.4 to be 3 seconds.

(config)# router ospf 1

(config-router-ospf)# transmit-delay 5

(config-router-ospf)# area 1.2.3.4 transmit-delay 3

(config-router-ospf)# exit

(config)#

area advertise-subnet

Name

area advertise-subnet - specifies whether OSPF will, when advertising point-to-point interfaces, advertise the network number and netmask instead of a host route to the remote IP

Syntax

area area_id advertise-subnet

no area area_id advertise-subnet

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

Description

The area advertise-subnet command specifies whether OSPF will, when advertising point-to-point interfaces, advertise the network number and netmask of the point-to-point interface instead of a host route to the remote IP. Because the netmask is sometimes set improperly on point-to-point interfaces, this option disabled by default.

Configuring this command in an area overrides a global advertise-subnet command. Similarly, this command can be overridden in an interface command.

Default

If area advertise-subnet is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# no area area_id advertise-subnet

Command History

NGC 2.2 - This command was introduced.

Examples

The following example turns advertise-subnet on for area 1.2.3.4 and off for interface fxp1 in the same area.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 advertise-subnet

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# no ip ospf advertise-subnet

(config-if)# exit

(config)#

See Also

"advertise-subnet"

area authentication

Name

area authentication - specifies the type of OSPF authentication used and any key values

Syntax

area area_id authentication [ [simple key] |
[ md5 id_number md5_key [(start-generate date_time) ||
(stop-generate date_time) || (start-accept date_time)
(stop-accept date_time)]? ] ]

no area area_id authentication [ simple key | md5 id_number]

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

simple key - specifies simple (clear password) authentication. The value for key is specified as a one- to eight-character string.

Description

The area authentication command specifies the type of authentication and key values used in OSPF. The negative form of this command removes authentication for the area. Authentication is used by OSPF to generate and verify the authentication field in the OSPF header. The global authentication is the default and can be overridden here in the area command. Similarly, this command can be overridden at the interface level.

Note: In order to turn off authentication, you must include the authentication type in the no form of the command. For example, if MD5 authentication was configured, then simply specifying no area authentication will not work. In addition, you must specify the simple key when turning off simple authentication, and you must specify the MD5 id_number when turning off MD5 authentication.

Default

The default is for no authentication to be explicitly configured.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures simple authentication in OSPF instance 1.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 authentication simple abc

(config-router-ospf)# exit

(config)#

Example 2

The following example configures md5 authentication for OSPF area 1.2.3.4. The ID for this md5 configuration is 1, and the key is configured as "bar".

(config)# router ospf 2

(config-router-ospf)# area 1.2.3.4 authentication md5 1 bar

(config-router-ospf)# exit

(config)#

Example 3

The following example turns off the MD5 authentication that was configured in Example 2. Note that specifying the MD5 key is not required, but specifying the MD5 ID is.

(config)# router ospf 2

(config-router-ospf)# no area 1.2.3.4 authentication md5 1

(config-router-ospf)# exit

(config)#

Example 4

(config)# router ospf 3

(config-router-ospf)# area 1.1.1.1 authentication md5 2
md5 start-generate 2004-01-02.21.30 stop-generate
2004-01-02.21.45 start-accept 2004-01-02.21.00
stop-accept 2004-01-02.22.00

(config-router-ospf)# exit

(config)#

See Also

"authentication"

area dead-interval

Name

area dead-interval - specifies the number of seconds that can elapse without receiving a router’s hello packets before the router’s neighbors will declare it down

Syntax

area area_id dead-interval time-seconds

no area area_id dead-interval time-seconds?

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

time-seconds - an integer between 1 and 65535, inclusive specifying an amount of time in seconds

Description

Use the area dead-interval command to specify the amount of time, in seconds, that can elapse without receiving a router’s hello packets before the router’s neighbors will declare it down. This command is specified here at the area level, and it can be overridden in the equivalent interface command. (See "ip ospf dead-interval".)

A general rule for configuring this value is that it should be equal to four times the HELLO interval. (See "area hello-interval".) Do not set this value to less than the HELLO interval because convergence will not occur.

The negative form of this command, no area dead-interval, removes the configured time-seconds value and returns this to its default value of 40 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If area dead-interval is not configured, it is the same as if the user had specified the following:

(config-router-ospf)# area area_id dead-interval 40

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a dead-interval of 80 seconds for area 1.2.3.4, and a dead-interval of 60 seconds on interface fxp1.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 dead-interval 80

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf dead-interval 60

(config-if)# exit

(config)#

See Also

"dead-interval"

area filter

Name

area filter - filters incoming summary (type 3) LSAs for an area

Syntax

area area_id filter ipv4_address netmask

no area area_id filter ipv4_address netmask

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

ipv4_address - a valid IPv4 filter address specified in dotted-quad format

netmask - a valid network mask specified in dotted-quad format

Description

The area filter command filters incoming summary (type 3) LSAs for the area. Any incoming summary LSA that falls within the given range will not be advertised into the area. This command has no effect unless the router is an ABR. This command has no effect in Transit areas (i.e. areas containing a Virtual Link). It is recommended that this command only be used in stub or NSSA areas that have a default being originated into them. Otherwise, addresses falling within the range may not be reachable in the area.

The negative form of this command, no area filter, removes the configured address range from the filter.

Default

This command is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example filters summary LSAs in the range 192.168.2.0 255.255.255.0.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 filter 192.168.2.0 255.255.255.0

(config-router-ospf)# exit

(config)#

area hello-interval

Name

area hello-interval - specifies the length of time in seconds between Hello packets that the router sends

Syntax

area area_id hello-interval time-seconds

no area area_id hello-interval time-seconds

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

time-seconds - an integer between 1 and 65535, inclusive, specifying an amount of time in seconds

Description

Use the area hello-interval command to specify the number of seconds between Hello packets sent by this router. This command is specified here at the area level, and it can be overridden in the equivalent interface command. (See "ip ospf hello-interval".)

A general rule for configuring this value is that it should be equal to one-fourth the dead interval. (See "area dead-interval".) This value should never be less than the dead interval value.

The negative form of this command, no area hello-interval, removes the configured time-seconds value and returns this to its default value of 10 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If area hello-interval is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# area area_id hello-interval 10

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a hello interval of 20 seconds for area 1.2.3.4, and a hello interval of 15 seconds on interface fxp1.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 hello-interval 20

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf hello-interval 15

(config-if)# exit

(config)#

See Also

"ip ospf hello-interval"

area nssa

Name

area nssa - configures the area as a Not So Stubby Area (NSSA) according to draft-ietf-ospf-nssa-update-11

Syntax

area area_id nssa metric metric-type

no area area_id nssa

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

metric - the default OSPF metric. This value can be an integer from 1 to 65535, inclusive. If area nssa is configured, then the default is to not originate a default route into the area.

metric-type - specify 1 or 2 as the default metric type. Routes exported from the Advanced Routing Suite routing table into OSPF default to becoming type 1 ASEs.

Description

The area nssa command configures the specified area as an NSSA according to draft-ietf-ospf-nssa-update-11. If the router is an ABR and has the highest router ID of all the ABRs in the area, and no other ABR in the area is configured to translate always, it will translate Type 7 LSAs with the P-bit (set by the propagate flag in an export command) to Type 5 LSAs. When an ABR that was translating loses a translator election, it will cease translating, and after a number of seconds (determined by the "nssa-stability-interval"), it will flush any Type 5 LSAs resulting from aggregation. Any Type 5 LSAs resulting from direct translation of Type 7 LSAs will be allowed to age out.

If metric is configured, then an ABR will originate a default route with that metric into the area. If there are any filters on the area, this will be a type-3 default. Otherwise it will be a type-7 default, with metric type of metric-type.

Note: NSSA and Stub are mutually exclusive.

Default

This command is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example changes the default metric type to 2.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 nssa 10 2

(config-router-ospf)# exit

(config)#

area nssa-range

Name

area nssa-range - specifies the net ranges that should be translated into Type 5 LSAs from NSSA Type 7 LSAs

Syntax

area area_id nssa-range ip_address mask [no-advertise]?

no area area_id nssa-range ip_address mask [no-advertise]?

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

ip_address - the IPv4 address associated with this range

mask - the network mask for the specified IP address

no-advertise - sets the address range status to DoNotAdvertise. The Type 3 summary LSA will not be suppressed, and the component networks will remain hidden from other networks. Specifying this is optional.

Description

The area nssa-range command specifies the net ranges that should be translated into Type 5 LSAs from NSSA Type 7 LSAs. The default behavior is to translate Type 7 LSas that do not fall within a configured net range. This command is valid only in an NSSA. It will be ignored when configured in a non-NSSA.

Default

NSSA net ranges are not configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures an NSSA range on address 192.168.110.0 with a mask of 255.255.0.0.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 nssa-range 192.168.110.0 255.255.0.0

(config-router-ospf)# exit

(config)#

area nssa-translate-always

Name

area nssa-translate-always - allows an Area Border Router (ABR) to always translate Type 7 LSAs into Type 5 LSAs for the specified area

Syntax

area area_id nssa-translate-always

no area area_id nssa-translate-always

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

Description

An NSSA ABR can translate Type 7 LSAs into Type 5 LSAs. Ordinarily, a translator election is run to determine which on ABR for a given NSSA will translate. This option, however, allows an ABR to always translate Type 7 LSAs into Type 5 LSAs for the containing area. If an ABR is configured to always translate, then no other ABR will translate unless it is also configured to always translate.

Default

If area nssa-translate-always is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# no area area_id nssa-translate-always

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures area 1.2.3.4 to always translate Type 7 LSAs into Type 5 LSAs.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 nssa-translate-always

(config-router-ospf)# exit

(config)#

area poll-interval

Name

area poll-interval - specifies the length of time, in seconds, between OSPF packets that the router send before adjacency is established with a neighbor

Syntax

area area_id poll-interval time-seconds

no area area_id poll-interval time-seconds?

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

time-seconds - the length of time in seconds, specified as an integer between 1 and 65535, inclusive

Description

The area poll-interval command specifies the length of time, in seconds, between OSPF packets that the router sends before adjacency is established with a neighbor. Utilizing this command reduces network overhead in cases where a router may have a neighbor on a given interface at the expense of initial convergence time.

Specifying a poll interval for an area overrides the default configured poll interval. Similarly, an interface-specific poll interval overrides a value configured here.

The negative form of this command, no area poll-interval, removes the configured time-seconds value and returns this to its default value of 120 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If area poll-interval is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# area area_id poll-interval 120

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures an area poll interval of 100 seconds. This value is overridden in interface fxp1, where it is configured to be 110 seconds.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 poll-interval 100

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf poll-interval 110

(config-if)# exit

(config)#

See Also

"poll-interval"

area priority

Name

area priority - specifies the priority for becoming the designated router (DR)

Syntax

area area_id priority level

no area area_id priority level?

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

level - a priority number between 0 and 255, inclusive, for becoming a DR

Description

The area priority command specifies the priority for becoming the DR. The priority specified at the area level can be overridden at the interface level. When more than one router attached to a network attempts to become the DR, the one with the highest priority wins. If the competing routers have the same priority, the one with the highest router ID becomes the DR. The router coming in second in the election becomes the backup DR. A router with a priority set to 0 is ineligible to become the DR.

Note: This command applies only to broadcast or NBMA media.

The negative form of this command, no area priority, removes the configured priority and returns this to its default value of 0. Note: Specifying a value for level in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If the area priority command is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# area area_id priority 1

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures an area priority of 10. It also configures the priority for interface fxp1 to be 5.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 priority 10

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf priority 5

(config-if)# exit

(config)#

See Also

"priority"

"ip ospf priority"

area range

Name

area range - configures the scope of an area on an Area Border Router (ABR)

Syntax

area area_id range ip_address mask [no-advertise]?

no area area_id range ip_address mask [no-advertise]?

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

ip_address - the IPv4 address associated with this range

mask - the network mask for the specified IP address

Description

The area range command configures the scope of an area on an ABR. Intra-area LSAs that fall within the specified ranges are not advertised into other areas as inter-area routes. Instead, the specified ranges are advertised as summary network LSAs. If no-advertise is specified, the summary network LSAs and all LSAs within the range are not advertised. Intra-area LSAs that do not fall into any range are also advertised as summary network LSAs.

On well-designed networks, the area range command reduces the amount of routing information propagated between areas. The entries in this command can be either networks or subnetwork/mask-length pairs.

Specifying the area range command on a non-ABR will have no effect. The negative form of this command removes the configured summarization.

Default

The area range command is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures an area range on address 192.168.0.0 with a mask of 255.255.0.0.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 range 192.168.0.0 255.255.0.0

(config-router-ospf)# exit

(config)#

area retransmit-interval

Name

area retransmit-interval - specifies the number of seconds between link state advertisement (LSA) retransmissions for adjacencies

Syntax

area area_id retransmit-interval time-seconds

no area area_id retransmit-interval time-seconds?

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

time-seconds - an integer between 1 and 65535, inclusive, specifying a number of seconds

Description

The area retransmit-interval command sets the default for the number of seconds between LSA retransmissions for adjacencies. If a Link State Protocol (LSP) is not acknowledged within the amount of time specified in this command, then it is re-sent. This setting is another convergence/network traffic trade-off.

This command overrides the global retransmit interval and can be overridden at the interface level. The negative form of this command, no area retransmit-interval, removes the configured value and returns this to its default value of 5 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If area retransmit-interval is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# area area_id retransmit-interval 5

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the retransmit interval for area 1.2.3.4 to be 10 seconds. This value is then overridden in interface fxp1, where it is configured to be 7 seconds.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 retransmit-interval 10

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf retransmit-interval 7

(config-if)# exit

(config)#

See Also

area stub

Name

area stub - configures an area as a stub area

Syntax

area area_id stub metric?

no area area_id stub metric?

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

metric - an integer between 1 and 65535, inclusive. If a stub area is configured, then the default is to not originate a default route into the area.

Description

The area stub command configures the specified area as a stub. A stub area is one in which there are no ASE or NSSA routes. Each router in the area must specify that the area is a stub, or adjacencies will not form. If a metric is specified, then it is used to inject a default route into the area with the specified value originating from this router. A metric value should only be specified on an Area Border Router (ABR). It is possible to use stub on multiple ABRs and give them different metrics.

The negative of this command, no area stub, removes the configured stub area.

Note: NSSA and stub are mutually exclusive.

Default

The default type of area is non-stub and non-NSSA. The default for a stub area is to not advertise a type-3 summary. A default is only originated if a cost is given.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures area 4.3.2.1 as a stub area with a metric of 15.

(config)# router ospf

(config-router-ospf)# area 4.3.2.1 stub 15

(config-router-ospf)# exit

(config)#

area stubhost

Name

area stubhost - specifies directly attached hosts that should be advertised as reachable from the router and the metrics with which they should be advertised

Syntax

area area_id stubhost ip_address metric_value

no area area_id stubhost ip_address metric_value

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

ip_address - the address of the host to be advertised

metric_value - the metric to be advertised for the host specified as an integer between 1 and 65535, inclusive. If a stubhost is configured, then this value defaults to 10.

Description

Use the area stubhost command to specify directly attached hosts that should be advertised as reachable from the router and the metrics with which they should be advertised. Point-to-point interfaces on which it is not desirable to run OSPF should be specified here. It is also useful to assign an additional address to the loopback interface (one not on the 127 network) and advertise it as a stubhost.

If this address is the same as the router ID, it enables routing to OSPF routers by router ID instead of by interface address. Routing by router ID is more reliable than routing to one of the router’s interface addresses, which may not always be reachable.

The negative of this command, no area stubhost, removes the configured stubhost.

Note: This command is identical to "area stubnetwork" in function except that a 32-bit mask is assumed.

Default

The area stubhost command is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a single stubhost, 192.1.1.1 with a metric of 2 in area 1.2.3.4.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 stubhost 192.1.1.1 2

(config-router-ospf)# exit

(config)#

area stubnetwork

Name

area stubnetwork - specifies directly attached networks that should be advertised as reachable from this router and the metrics with which they should be advertised

Syntax

area area_id stubnetwork ip_address mask metric

no area area_id stubnetwork ip_address mask metric

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

ip_address - the address of the host to be advertised

mask - a mask for a network prefix specified in dotted-quad format

metric - the metric for the stubnetwork specified as an integer between 1 and 65535, inclusive. If a stubnetwork is configured, then this value defaults to 10.

Description

Use the area stubnetwork command to specify directly attached networks that should be advertised as reachable from this router. Interfaces on which it is not desirable to run OSPF should be specified here. No checking is currently done on whether the specified network is actually reachable from this router, so care should be taken.

The negative form of this command, no area stubnetwork, removes the configured stubnetwork.

Note: This command is identical to "area stubhost" in function except that a 32-bit mask is not assumed and, therefore, must be configured.

Default

The area stubnetwork command is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a single stubnetwork, 192.168.10 with a netmask of 24 in area 1.2.3.4.

(config)# router ospf 2

(config-router-ospf)# area 1.2.3.4 stubnetwork 192.168.10 255.255.255.0

(config-router-ospf)# exit

(config)#

area transmit-delay

Name

area transmit-delay - specifies the number of seconds required to transmit a link state update

Syntax

area area_id transmit-delay time-seconds

no area area_id transmit-delay time-seconds?

Mode

OSPF Router Configuration

Parameters

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

time-seconds - the length of time in seconds, between 1 and 65535, inclusive specified as an integer

Description

The area transmit-delay command sets the estimated number of seconds required to transmit a link state update. This value takes into account transmission and propagation delays and must be greater than 0.

This value overrides the global transmit-delay value and can be overridden at the interface level. The negative form of this command, no area transmit-delay, removes the configured value and returns this to its default value of 1 second. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If area transmit-delay is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# area area_id transmit-delay 1

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the transmit-delay for area 1.2.3.4 to be 10 seconds. This value is then overridden on interface fxp1, where it is configured to be 5 seconds.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 transmit-delay 10

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf transmit-delay 5

(config-if)# exit

(config)#

See Also

"ip ospf transmit-delay"

area virtual-link

Name

area virtual-link - configures a virtual link on the backbone

Syntax

area transit_area virtual-link neighbor-id
[ authentication [ (md5 id md5key) |
(simple key) ] ]? ||
[(hello-interval time-seconds) ]? ||
[(retransmit-interval time-seconds) ]? ||
[(transmit-delay time-seconds) ]? ||
[(dead-interval time-seconds) ]?

no area transit_area virtual-link neighbor-id
[ authentication [ (md5 id md5key) |
(simple key) ] ]? ||
[(hello-interval time-seconds) ]? ||
[(retransmit-interval time-seconds) ]? ||
[(transmit-delay time-seconds) ]? ||
[(dead-interval time-seconds) ]?

Mode

OSPF Router Configuration

Parameters

transit_area - an ID, in dotted-quad format, that sets the area through which the virtual link should exist. This value cannot be 0.0.0.0.

neighbor-id - the ID of one end of the virtual link

[authentication [ (md5 id "md5key") | (simple "key") ]] - optionally specify an authentication type to include on this virtual link. md5 id md5_key specifies the authentication used for specifying md5 cryptographic authentication. The value for id is an integer between 1 and 255, inclusive. The value for md5_key is a one- to sixteen-character string. simple key specifies simple (clear password) authentication. The value for key is as a one- to eight-character string.

hello-interval time-seconds - optionally specify the time in seconds between hello packets that the IOS software sends on an interface. This value must be an unsigned integer and must be the same for all routers and access servers attached to a common network. The default value is 10 seconds.

retransmit-interval time-seconds - optionally specify the time in seconds between link state advertisement (LSA) retransmissions for adjacencies belonging on the interface. This value must be an integer and must be greater than the expected round-trip delay. The default value is 5 seconds.

transmit-delay time-seconds - optionally specify the time in seconds required to send a link state update packet on the interface. This value must be an integer greater than 0. LSAs in the update packet have their age incremented by this amount before transmission. The default value is 1 second.

dead-interval time-seconds - optionally specify the time in seconds that Hello packets are sent before a neighbor declares the router down. The default value is four times the hello-interval, or 40 seconds. If this value is configured less than the hello-interval, convergence will not occur. This value must be the same for all routers and access servers attached to a common network.

Description

Virtual links are used to establish or increase connectivity of the backbone area. The transit_area sets the area through which the virtual link should exist. The neighbor-id represents one end of the virtual link. In addition, all standard interface parameters can optionally be specified on a virtual link.

The negative form of this command, no area virtual-link, removes the configured virtual link. The transit_area and neighbor-id parameters are the minimum required in the negative form of this command to remove the entire virtual link.

Default

The default is for no virtual links to be explicitly configured.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a virtual link in transit area 1.1.1.1 with a neighbor ID of 1.2.2.1, a hello interval of 20 seconds, and a retransmit interval of 20 seconds.

(config)# router ospf 1

(config-router-ospf)# area 1.1.1.1 virtual-link 1.2.2.1
hello-interval 20 retransmit-interval 20

(config-router-ospf)# exit

(config)#

default-metric

Name

default-metric - specifies the default ASE export metric

Syntax

default-metric metric_value

no default-metric metric_value?

Mode

OSPF Router Configuration

Parameters

metric_value - an integer assigned to exported reachability, specified as a value between 1 and 65535, inclusive

Description

This command is used when exporting a non-OSPF route from the Advanced Routing Suite routing table into OSPF as an ASE route. The default-metric command can be explicitly overridden in export policy.

The negative of this command, no default-metric, removes the configured value and returns this to its default value of 10. Note: Specifying a value for metric_value in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If default-metric is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# default-metric 10

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a default metric of 5 for instance 1.

(config)# router ospf 1

(config-router-ospf)# default-metric 5

(config-router-ospf)# exit

(config)#

default-nssa-metric

Name

default-nssa-metric - specifies the default cost when exporting non-OSPF routes into OSPF NSSA

Syntax

default-nssa-metric metric_value

no default-nssa-metric metric_value?

Mode

OSPF Router Configuration

Parameters

metric_value - an integer assigned to exported reachability, specified as a value between 1 and 65535, inclusive

Description

default-nssa-metric is used when exporting a non-OSPF route from the Advanced Routing Suite routing table into OSPF as an NSSA route. This command configures the default metric on originated NSSA routes for an OSPF instance. default-nssa-metric can be explicitly overridden in export policy.

The negative form of this command, no default-nssa-metric, removes the configured value and returns the metric_value to its default of 1. Note: Specifying a value for metric_value in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If default-nssa-metric is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# default-nssa-metric 10

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the default NSSA metric for OSPF instance 1 to be 4.

(config)# router ospf 1

(config-router-ospf)# default-nssa-metric 4

(config-router-ospf)# exit

(config)#

default-nssa-type

Name

default-nssa-type - changes the default type of routes exported from the Advanced Routing Suite routing table into OSPF NSSA

Syntax

default-nssa-type [1 | 2]

no default-nssa-type [1 | 2]?

Mode

OSPF Router Configuration

Parameters

1 | 2 - sets the default metric type to 1 or 2

Description

The default-nssa-type command sets the default NSSA metric type to either 1 or 2. Routes exported from the Advanced Routing Suite routing table into OSPF default to becoming type 1 NSSAs. This default can be explicitly change here and overridden in export policy.

The negative form of this command, no default-nssa-type, removes the configured value and returns this to its default value of 1. Note: Specifying type 1 or 2 in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If default-nssa-type is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# default-nssa-type 1

Command History

NGC 2.2 - This command was introduced.

Examples

The following example changes the default NSSA Type to 2.

(config)# router ospf 2

(config-router-ospf)# default-nssa-type 2

(config-router-ospf)# exit

(config)#

default-preference

Name

default-preference - specifies the way that active routes learned from the OSPF ASE will be selected, compared to other routes

Syntax

default-preference pref

no default-preference pref?

Mode

OSPF Router Configuration

Parameters

pref - an integer between 1 and 255, inclusive

Description

The default-preference command specifies how active routes that are learned from the OSPF ASE (compared to other routes) will be selected. When a route has been learned from more than one protocol, the active route will be selected from the protocol with the lowest preference. Each protocol has a default preference in this selection.

The negative form of this command, no default-preference, removes the configured preference value and returns this to its default value of 10. Note: Specifying a value for pref in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If default-preference is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# default-preference 10

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the OSPF default preference value to be 100.

(config)# router ospf 2

(config-router-ospf)# default-preference 100

(config-router-ospf)# exit

default-tag

Name

default-tag - used to propagate data from an exterior gateway protocol (such as BGP) through OSPF

Syntax

default-tag tag_value

no default-tag tag_value?

Mode

OSPF Router Configuration

Parameters

tag_value - a integer from 0 to 2147483647, inclusive

Description

OSPF ASE routes have a 32-bit tag field that is not used by the OSPF protocol but can be used when exporting to protocols other than OSPF. This command sets the tag, which can be overridden in export policy.

The negative form of this command, no default-tag, removes the configured tag value and returns this to its default value of 0. Note: Specifying a value for tag_value in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If default-tag is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# default-tag 0

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the default tag value to be 10.

(config)# router ospf 1

(config-router-ospf)# default-tag 10

(config-router-ospf)# exit

(config)#

default-type

Name

default-type - changes the default type of routes exported from the Advanced Routing Suite routing table into OSPF ASE

Syntax

default-type [1 | 2]

no default-type [1 | 2]?

Mode

OSPF Router Configuration

Parameters

1 | 2 - sets the default metric type to 1 or 2

Description

Routes exported from the Advanced Routing Suite routing table into OSPF default to becoming type 2 ASEs. This default can be explicitly changed here and overridden in export policy.

The negative form of this command, no default-type, removes the configured value and returns this to its default value of 1. Note: Specifying 1 or 2 as the type in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If default-type is not specified, it is the same as if the user had specified the following:

(config-router-ospf)# default-type 2

Command History

NGC 2.2 - This command was introduced.

Examples

The following example changes the default metric type to 1.

(config)# router ospf 2

(config-router-ospf)# default-type 1

(config-router-ospf)# exit

(config)#

advertise-subnet

Name

advertise-subnet - specifies whether OSPF will, when advertising point-to-point interfaces, advertise the network number and netmask of the point-to-point interface instead of a host route to the remote IP

Syntax

advertise-subnet

no advertise-subnet

Mode

Area Interface Configuration

Parameters

none

Description

Default

If advertise-subnet is not specified, it is the same as if the user had specified the following:

(config-if-ip-ospf)# no advertise-subnet

Command History

NGC 2.3 - This command was introduced.

Examples

The following example turns advertise-subnet on for area 2.2.2.2 on interface ppp0.

(config)# interface ppp0

(config-if)# ip ospf 1 area 2.2.2.2

(config-if-ip-ospf)# advertise-subnet

(config-if-ip-ospf)# exit

(config-if)#

See Also

allow-all

Name

allow-all - permits packets from all routers

Syntax

allow-all

no allow-all

Mode

Area Interface Configuration

Parameters

none

Description

The allow-all command specifies to allow packets from all routers, including those not specified in the "neighbor" command.

Default

If allow-all is not specified, it is the same as if the user had specified the following:

(config-if-ip-ospf)# no allow-all

Command History

NGC 2.3 - This command was introduced.

Examples

The following example specifies that area 1.2.3.4 on interface fxp1 will allow packets from all routers.

(config)# interface fxp1

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# allow-all

(config-if-ip-ospf)# exit

(config-if)#

See Also

authentication

Name

authentication - specify the type of authentication and key values for an interface

Syntax

authentication [ [simple key] | [ md5 id_number md5_key
[(start-generate date_time) ||
(stop-generate date_time) || (start-accept date_time)
(stop-accept date_time)]? ] ]

no authentication [ simple key | md5 id_number ]

Mode

Area Interface Configuration

Parameters

simple key - specifies simple (clear password) authentication. The value for key is specified as a one- to eight-character string.

Description

The authentication command specifies the type of authentication and key values used for an area on an interface. This is used by OSPF authentication to generate and verify the authentication field in the OSPF header. If configured, the area authentication ("area authentication") is the default unless it is configured here at the area interface level.

Default

Authentication is not explicitly configured by default.

Command History

NGC 2.3 - This command was introduced.

Examples

Example 1

The following example configures the global authentication to be the simple keyword "abc". This authentication is then overridden for area 1.2.3.4 on interface fxp0 to be "bar".

(config)# router ospf 1

(config-router-ospf)# authentication simple abc

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# authentication simple bar

(config-if-ip-ospf)# exit

(config-if)#

Example 2

The following example configures md5 authentication for area 2.2.2.2 on interface fxp1. The ID for this md5 configuration is 1, and the key is configured as "bar".

(config)# interface fxp1

(config-if)# ip ospf 1 area 2.2.2.2

(config-if-ip-ospf)# authentication md5 1 bar

(config-if-ip-ospf)# exit

(config-if)#

Example 3

The following example turns off the MD5 authentication that was configured in Example 2.

(config)# interface fxp1

(config-if)# ip ospf 1 area 2.2.2.2

(config-if-ip-ospf)# no authentication md5 1

(config-if-ip-ospf)# exit

(config-if)#

Example 4

The following example configures md5 authentication for area 4.3.2.1 on interface fxp3. The md5 authentication is configured with a start-generate time set to January 02, 2004 at 21:30 hours, a stop-generate time set to January 02, 2004 at 21:45 hours, a start-accept time set to January 02, 2004 at 21:00 hours, and a stop-accept time set to January 02, 2004 at 22:00 hours.

(config)# interface fxp3

(config-if)# ip ospf 1 area 4.3.2.1

(config-if-ip-ospf)# authentication md5 2 md5
start-generate 2004-01-02.21.30 stop-generate
2004-01-02.21.45 start-accept 2004-01-02.21.00
stop-accept 2004-01-02.22.00

(config-if-ip-ospf)# exit

(config-if)#

See Also

"authentication"

cost

Name

cost - specifies the cost for a route to transmit an interface

Syntax

cost cost_value

no cost cost_value?

Mode

Area Interface Configuration

Parameters

cost_value - the cost to be associated with this interface, specified as an integer between 1 and 65535

Description

The cost command is used for specifying the cost for a route to transmit an interface. This command can be explicitly overridden in export policy. The negative form of this command, no cost, removes the configured cost and returns this to its default value of 1. Note: Specifying a value for cost_value in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If cost is not specified, it is the same as if the user had specified the following:

(config-if-ip-ospf)# cost 10

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures the cost for area 1.2.3.4 on interface fxp1 to be 15.

(config)# interface fxp1

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# cost 15

(config-if-ip-ospf)# exit

(config-if)#

See Also

dead-interval

Name

dead-interval - specifies the number of seconds that may elapse on this interface without receiving a router’s hello packets before the router’s neighbors will declare it down

Syntax

dead-interval time-seconds

no dead-interval time-seconds?

Mode

Area Interface Configuration

Parameters

time-seconds - an integer between 1 and 65535, inclusive, specifying an amount of time in seconds

Description

Use the dead-interval command to specify the amount of time, in seconds, that can elapse without receiving a router’s hello packets before the router’s neighbors will declare it down. This command is specified here at the interface level. It overrides a dead-interval configured at the area and global levels.

A general rule for configuring this value is that it should be equal to four times the HELLO interval. (See "hello-interval".) Do not set this value to less than the HELLO interval because convergence will not occur.

The negative form of this command, no dead-interval, removes the configured time-seconds value and returns this to its default value of 40 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If dead-interval is not specified, it defaults to the value specified in "area dead-interval" then the global "dead-interval". If neither of these is specified, however, then it is the same as if the user had specified the following:

(config-if-ip-ospf)# dead-interval 40

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures a global dead-interval of 80 seconds and a dead-interval of 60 seconds for area 1.2.3.4 on interface fxp1.

(config)# router ospf 1

(config-router-ospf)# dead-interval 80

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# dead-interval 60

(config-if-ip-ospf)# exit

(config-if)#

See Also

"dead-interval"

enable

Name

enable - enables OSPF on an interface

Syntax

enable

no enable

Mode

Area Interface Configuration

Parameters

none

Description

The enable command specifies to run OSPF on an interface.

Default

By default, OSPF runs on configured interfaces. Therefore, if enable is not specified, it is the same as if the user had specified the following:

(config-if-ip-ospf)# enable

Command History

NGC 2.3 - This command was introduced.

Examples

The following example disables interface fxp1 for area 1.2.3.4.

(config)# interface fxp1

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# no enable

(config-if-ip-ospf)# exit

(config-if)#

See Also

hello-interval

Name

hello-interval - specifies the length of time in seconds between hello packets that the router sends on the interface for the specified area

Syntax

hello-interval time-seconds

no hello-interval time-seconds?

Mode

Area Interface Configuration

Parameters

time-seconds - an integer between 1 and 65535, inclusive, specifying an amount of time in seconds

Description

Use the hello-interval command to specify the number of seconds between Hello packets sent by the router on this interface for the specified area. This command overrides the interval configured in the equivalent global and area commands. (See "hello-interval" and "area hello-interval".)

A general rule for configuring this value is that it should be equal to one-fourth the dead interval. (See "dead-interval".) This value should never be less than the dead interval value.

The negative form of this command, no hello-interval, removes the configured time-seconds value. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If hello-interval is not specified, it defaults to the value specified in "area hello-interval" then in the global "hello-interval". If neither the area nor global hello interval is specified, however, then it is the same as if the user had specified the following:

(config-if-ip-ospf)# hello-interval 10

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures a global hello interval of 20 seconds and a hello interval of 15 seconds for area 1.2.3.4 on interface fxp1.

(config)# router ospf 1

(config-router-ospf)# hello-interval 20

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# hello-interval 15

(config-if-ip-ospf)# exit

(config-if)#

See Also

"hello-interval"

neighbor

Name

neighbor - specifies neighboring routes, and specifies whether those routes are eligible to become the designated router (DR)

Syntax

neighbor ip_address [eligible]?

no neighbor ip_address [eligible]?

Mode

Area Interface Configuration

Parameters

ip_address - a valid IPv4 address specified in dotted-quad notation

eligible - optionally specify whether the indicated address is eligible to become the DR

Description

By definition it is not possible to send broadcast or multicast packets to discover OSPF neighbors on a non-broadcast medium, so all neighbors must be configured. The host address list includes one or more neighbors. The eligible option is used to indicate an address’s eligibility to become a DR. Refer to section 9.5.1 of RFC 2328 for more information.

The negative form of this command, no neighbor, removes the configured neighbors.

Default

OSPF neighbors are not explicitly configured by default.

Command History

NGC 2.3 - This command was introduced.

Examples

The following example specifies that host 10.1.1.1 is eligible to become a DR in area 2.2.2.2.

(config)# interface fxp1

(config-if)# ip ospf 1 area 2.2.2.2

(config-if-ip-ospf)# neighbor 10.1.1.1 eligible

(config-if-ip-ospf)# exit

See Also

network

Name

network - specifies a either a nonbroadcast interface on an NBMA medium or a point-to-multipoint interface

Syntax

network [ nonbroadcast | point-to-multipoint ]

no network [ nonbroadcast | point-to-multipoint ]

Mode

Area Interface Configuration

Parameters

nonbroadcast - specifies a nonbroadcast interface on an NBMA medium

point-to-multipoint - specifies a point-to-multipoint interface

Description

Use the network command to specify either a nonbroadcast or point-to-point interface. Because an OSPF broadcast medium must support IP multicasting, a broadcast-capable medium that does not support IP multicasting must be configured as a nonbroadcast interface. This includes the loopback interface on many operating systems.

Default

The default mode is broadcast/point-to-point; therefore this command is not explicitly configured by default.

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures interface lo1 as a nonbroadcast interface in area 2.2.2.2.

(config)# interface lo1

(config-if)# ip ospf 1 area 2.2.2.2

(config-if-ip-ospf)# network nonbroadcast

(config-if-ip-ospf)# exit

(config-if)#

See Also

no-multicast

Name

no-multicast - disables multicast on a specified interface

Syntax

no-multicast

no no-multicast

Mode

Area Interface Configuration

Parameters

none

Description

The no-multicast command explicitly disables multicast for an area on a specified interface. The negative form of this command, no no-multicast, re-enables multicast on the area interface.

Default

By default, interfaces are multicast interfaces. Therefore, if no-multicast is not specified, it is the same as if the user had specified the following:

(config-if-ip-ospf)# no no-multicast

Command History

NGC 2.3 - This command was introduced.

Examples

The following example disables multicast for area 2.2.2.2 on interface fxp2.

(config)# interface fxp2

(config-if)# ip ospf 1 area 2.2.2.2

(config-if-ip-ospf)# no-multicast

(config-if-ip-ospf)# exit

(config-if)#

See Also

passive-interface

Name

passive-interface - disables reception and transmission on an interface for a specific area

Syntax

passive-interface

no passive-interface

Mode

Area Interface Configuration

Parameters

none

Description

This command specifies that Advanced Routing Suite will neither send nor receive packets on this interface. This is used, for example, when this is the only router on the network. This has the effect of originating a stub link to his interface into the domain.

Note: OSPF passive interface is not used to learn other routers’ announcements, which is the way passive works in RIP. If your host is connected to a single network on which there are multiple routers, use Router Discovery combined with ICMP redirects to learn a default route and the best route. If your host is connected directly to multiple networks, this method might produce the best routes.

The negative form of this command, no passive-interface, re-enables reception and transmission for an area on the interface.

Default

If passive-interface is not specified, it is the same as if the user had specified the following:

(config-if-ip-ospf)# no passive-interface

Command History

NGC 2.3 - This command was introduced.

Examples

The following example specifies to not send or receive packets on area 1.2.3.4 for interface fxp2.

(config)# interface fxp2

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# passive-interface

(config-if-ip-ospf)# exit

(config-if)#

See Also

poll-interval

Name

poll-interval - specifies the length of time, in seconds, between OSPF packets that the router send before adjacency is established with a neighbor

Syntax

poll-interval time-seconds

no poll-interval time-seconds?

Mode

Area Interface Configuration

Parameters

time-seconds - the length of time in seconds, specified as an integer between 1 and 65535, inclusive

Description

The poll-interval command specifies the length of time, in seconds, between OSPF packets that the router sends before adjacency is established with a neighbor. Utilizing this command reduces network overhead in cases where a router may have a neighbor on a given interface at the expense of initial convergence time.

Default

If poll-interval is not specified, it is the same as if the user had specified the following:

(config-if-ip-ospf)# poll-interval 120

Command History

NGC 2.3 - This command was introduced.

Examples

The following configures the poll-interval for area 1.2.3.4 on interface fxp0 to be 100 seconds.

(config)# interface fxp0

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# poll-interval 100

(config-if-ip-ospf)# exit

(config-if)#

See Also

"poll-interval"

priority

Name

priority - configures the area-specific priority on an interface for becoming the designated router (DR)

Syntax

priority level

no priority level?

Mode

Area Interface Configuration

Parameters

level - a priority number between 0 and 255, inclusive, for becoming a DR

Description

The priority command configures the area-specific priority on this interface for becoming the DR. This priority overrides any that is configured at the global or area levels. (See "priority" and "area priority".) When more than one router attached to a network attempts to become the DR, the one with the highest priority wins. If the competing routers have the same priority, the one with the highest router ID becomes the DR. The router coming in second in the election becomes the backup DR. A router with a priority set to 0 is ineligible to become the DR.

The negative form of this command, no priority, removes the configured priority. Note: Specifying a value for level in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Note: This command applies only to broadcast or NBMA media.

Default

If the priority command is not specified, then this value defaults to the configured area or global value, respectively. If neither of those is configured, then this value defaults to the following:

(config-if-ip-ospf)# priority 1

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures a global priority of 10. It also configures the priority for area 1.2.3.4 on interface fxp1 to be 5.

(config)# router ospf 1

(config-router-ospf)# priority 10

(config-router-ospf)# exit

(config)# interface fxp1

(config)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# priority 5

(config-if-ip-ospf)# exit

(config-if)#

See Also

retransmit-interval

Name

retransmit-interval - specifies the number of seconds between link state advertisement (LSA) retransmissions for adjacencies

Syntax

retransmit-interval time-seconds

no retransmit-interval time-seconds?

Mode

Area Interface Configuration

Parameters

time-seconds - the length of time in seconds, between 1 and 65535, inclusive specified as an integer

Description

This command overrides any configured in the global or area levels. (See "retransmit-interval" and "area retransmit-interval".)

The negative form of this command, no retransmit-interval, removes the configured retransmit value. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If the retransmit-interval command is not specified, then this value defaults to the configured area or global value, respectively. If neither of those is configured, then this value defaults to the following:

(config-if-ip-ospf)# retransmit-interval 5

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures the global retransmit interval f10 seconds. This value is then overridden in interface fxp1 for the area 1.2.3.4, where it is configured to be 7 seconds.

(config)# router ospf 1

(config-router-ospf)# retransmit-interval 10

(config-router-ospf)# exit

(config)# interface fxp1

(config-if-ip-ospf)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# retransmit-interval 7

(config-if-ip-ospf)# exit

(config-if)#

See Also

traffic-eng administrative-weight

Name

traffic-eng administrative-weight - sets the area-specific cost of the interface for Traffic Engineering purposes

Syntax

traffic-eng administrative-weight number

no traffic-eng administrative-weight number?

Mode

Area Interface Configuration

Parameters

number - an integer from 1 to 65535, inclusive

Description

Use the traffic-eng administrative-weight command to configure the cost of the interface for Traffic Engineering purposes. This cost can be different than the normal OSPF interface cost. The negative form of this command, no traffic-eng administrative-weight, removes the configured number value.

Notes:

Specifying a value for number in the no form has no effect on the configuration. Thus, it is displayed above as optional.
Traffic engineering must be enabled on the router before this command will take effect. See "enable-te".

Default

This command is not explicitly configured by default.

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures a traffic engineering cost of 6 for area 1.2.3.4 on interface fxp2.

(config)# router ospf 1

(config-router-ospf)# enable-te

(config-router-ospf)# exit

(config)# interface fxp2

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# traffic-eng administrative-weight 6

(config-if-ip-ospf)# exit

(config)#

See Also

traffic-eng attribute-flags

Name

traffic-eng attribute-flags - sets the OSPF Traffic Engineering attributes for the interface

Syntax

traffic-eng attribute-flags number

no traffic-eng attribute-flags number?

Mode

Area Interface Configuration

Parameters

number - an integer from 0 to 4,294,967,295, inclusive

Description

Use the traffic-eng attribute-flags command to sets the area-specific OSPF Traffic Engineering attributes for the interface. These flags can be used to indicate which link groups (or "colors") are present on the interface. The negative form of this command, no traffic-eng attribute-flags, removes the configured number value.

Notes:

Specifying a value for number in the no form has no effect on the configuration. Thus, it is displayed above as optional.
Traffic engineering must be enabled on the router before this command will take effect. See "enable-te".

Default

This command is not explicitly configured by default.

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures a traffic engineering attribute flag of 1 for area 1.2.3.4 on interface fxp2.

(config)# router ospf 1

(config-router-ospf)# enable-te

(config-router-ospf)# exit

(config)# interface fxp2

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# traffic-eng attribute-flags 1

(config-if-ip-ospf)# exit

(config-if)#

See Also

traffic-eng bandwidth

Name

traffic-eng bandwidth - sets the bandwidth of the interface

Syntax

traffic-eng bandwidth kbps

no traffic-eng bandwidth kbps

Mode

Area Interface Configuration

Parameters

kbps - an integer from 0 to 65535, inclusive, specifying a number of kilobytes per second

Description

The traffic-eng bandwidth command configures an area-specific bandwidth of the interface for Traffic Engineering information distributed within the OSPF domain. The negative form of this command, no traffic-eng bandwidth, removes the configured kbps value.

Notes:

Specifying a value for kbps in the no form has no effect on the configuration. Thus, it is displayed above as optional.
Traffic engineering must be enabled on the router before this command will take effect. See "enable-te".

Default

This command is not explicitly configured by default.

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures a traffic engineering bandwidth of 1000 kbps for area 1.2.3.4 on interface fxp2.

(config)# router ospf 1

(config-router-ospf)# enable-te

(config-router-ospf)# exit

(config)# interface fxp2

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# traffic-eng bandwidth 1000

(config-if-ip-ospf)# exit

(config-if)#

See Also

transmit-delay

Name

transmit-delay - specifies the number of seconds required to transmit a link state update

Syntax

transmit-delay time-seconds

no transmit-delay time-seconds?

Mode

Area Interface Configuration

Parameters

time-seconds - the length of time in seconds, between 1 and 65535, inclusive specified as an integer

Description

The transmit-delay command sets the estimated number of seconds required to transmit a link state update. This command takes into account transmission and propagation delays and must be greater than 0. This command overrides any given at the global or area levels ("transmit-delay" and "area transmit-delay").

The negative form of this command, no transmit-delay, removes the configured time-seconds value. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If transmit-delay is not specified, then this value defaults to the configured area or global value, respectively. If neither of those is configured, then this value defaults to the following:

(config-if-ip-ospf)# transmit-delay 1

Command History

NGC 2.3 - This command was introduced.

Examples

The following example configures the global transmit-delay for to be 10 seconds. This value is then overridden on interface fxp1 for area 1.2.3.4, where it is configured to be 5 seconds.

(config)# router ospf 1

(config-router-ospf)# transmit-delay 10

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)# transmit-delay 5

(config-if-ip-ospf)# exit

(config-if)#

See Also

"area transmit-delay"

"ip ospf transmit-delay"

ip ospf advertise-subnet

Name

ip ospf advertise-subnet - specifies whether OSPF will, when advertising point-to-point interfaces, advertise the network number and netmask of the point-to-point interface instead of a host route to the remote IP

Syntax

ip ospf advertise-subnet

no ip ospf advertise-subnet

Mode

Interface Configuration

Parameters

none

Description

The ip ospf advertise-subnet command specifies whether OSPF will, when advertising point-to-point interfaces, advertise the network number and netmask of the point-to-point interface instead of a host route to the remote IP. Because the netmask is sometimes set improperly on point-to-point interfaces, this option disabled by default.

Default

If ip ospf advertise-subnet is not specified, it is the same as if the user had specified the following:

(config-if)# no ip ospf advertise-subnet

Command History

NGC 2.2 - This command was introduced.

Examples

The following example turns advertise-subnet on for interface ppp0.

(config)# interface ppp0

(config-if)# ip ospf advertise-subnet

(config-if)# exit

(config)#

ip ospf allow-all

Name

ip ospf allow-all - permits packets from all routers

Syntax

ip ospf allow-all

no ip ospf allow-all

Mode

Interface Configuration

Parameters

none

Description

The ip ospf allow-all command specifies to allow packets from all routers, including those not specified in the "ip ospf neighbor" command.

Default

If ip ospf allow-all is not specified, it is the same as if the user had specified the following:

(config-if)# no ip ospf allow-all

Command History

NGC 2.2 - This command was introduced.

Examples

The following example specifies that interface fxp1 will allow packets from all routers.

(config)# interface fxp1

(config-if)# ip ospf allow-all

(config-if)# exit

(config)#

ip ospf area

Name

ip ospf area - configures an area ID for an interface

Syntax

ip ospf instance_id area area_id

no ip ospf instance_id area area_id

Mode

Interface Configuration

Parameters

instance_id - specifies to return information for a specific instance. This can be an integer from 1 to 4,294,967,294, inclusive.

area_id - an ID for an area specified as either a decimal value or as an IP address in dotted-quad format. A value of 0.0.0.0 signals that the area is a backbone.

Description

The ip ospf area command sets the OSPF area ID for an interface and enters the user into OSPF Area Interface Configuration mode. As a result, all remaining interface attributes can be configured for this area.

Default

This command is not explicitly configured by default.

Command History

NGC 2.3 - This command was introduced.

Examples

In the following example, area 1.2.3.4 is configured for interface fxp1.

(config)# interface fxp1

(config-if)# ip ospf 1 area 1.2.3.4

(config-if-ip-ospf)#

ip ospf authentication

Name

ip ospf authentication - specify the type of authentication and key values for an interface

Syntax

ip ospf authentication [ [simple key] |
[ md5 id_number md5_key [(start-generate date_time) ||
(stop-generate date_time) || (start-accept date_time)
(stop-accept date_time)]? ] ]

no ip ospf authentication [ simple key | md5 id_number ]

Mode

Interface Configuration

Parameters

simple key - specifies simple (clear password) authentication. The value for key is specified as a one- to eight-character string.

Description

The ip ospf authentication command specifies the type of authentication and key values used on an interface. This is used by OSPF authentication to generate and verify the authentication field in the OSPF header. If configured, the area authentication ("area authentication") is the default unless it is configured here at the interface level.

Note: In order to turn off authentication, you must include the authentication type in the no form of the command. For example, if MD5 authentication was configured, then simply specifying no ip ospf authentication will not work. In addition, you must specify the simple key when turning off simple authentication, and you must specify the MD5 id_number when turning off MD5 authentication.

Default

Authentication is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures the area authentication to be the simple keyword "abc". This authentication is then overridden for interface fxp0 to be "bar".

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 authentication simple abc

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf authentication simple bar

(config-if)# exit

(config)#

Example 2

The following example configures md5 authentication for interface fxp1. The ID for this md5 configuration is 1, and the key is configured as "bar".

(config)# interface fxp1

(config-if)# ip ospf authentication md5 1 bar

(config-if)# exit

(config)#

Example 3

The following example turns off the MD5 authentication that was configured in Example 2. Note that specifying the MD5 key is not required, but specifying the MD5 ID is.

(config)# interface fxp1

(config-if)# no ip ospf authentication md5 1

(config-if)# exit

(config)#

Example 4

The following example configures md5 authentication for interface fxp3. The md5 authentication is configured with a start-generate time set to January 02, 2004 at 21:30 hours, a stop-generate time set to January 02, 2004 at 21:45 hours, a start-accept time set to January 02, 2004 at 21:00 hours, and a stop-accept time set to January 02, 2004 at 22:00 hours.

(config)# interface fxp3

(config-if)# ip ospf authentication md5 2 md5
start-generate 2004-01-02.21.30 stop-generate
2004-01-02.21.45 start-accept 2004-01-02.21.00
stop-accept 2004-01-02.22.00

(config-if)# exit

(config)#

See Also

"authentication"

ip ospf cost

Name

ip ospf cost - specifies the cost for a route to transmit an interface

Syntax

ip ospf cost cost_value

no ip ospf cost cost_value?

Mode

Interface Configuration

Parameters

cost_value - the cost to be associated with this interface, specified as an integer between 1 and 65535

Description

The ip ospf cost command is used for specifying the cost for a route to transmit an interface. This command can be explicitly overridden in export policy. The negative form of this command, no ip ospf cost, removes the configured cost and returns this to its default value of 1. Note: Specifying a value for cost_value in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If ip ospf cost is not specified, it is the same as if the user had specified the following:

(config-if)# ip ospf cost 10

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the cost for interface fxp1 to be 15.

(config)# interface fxp1

(config-if)# ip ospf cost 15

(config-if)# exit

(config)#

ip ospf dead-interval

Name

ip ospf dead-interval - specifies the number of seconds that may elapse on this interface without receiving a router’s hello packets before the router’s neighbors will declare it down

Syntax

ip ospf dead-interval time-seconds

no ip ospf dead-interval time-seconds?

Mode

Interface Configuration

Parameters

time-seconds - an integer between 1 and 65535, inclusive, specifying an amount of time in seconds

Description

Use the ip ospf dead-interval command to specify the amount of time, in seconds, that can elapse without receiving a router’s hello packets before the router’s neighbors will declare it down. This command is specified here at the interface level. It overrides a dead-interval configured at the area and global levels.

A general rule for configuring this value is that it should be equal to four times the HELLO interval. (See "ip ospf hello-interval".) Do not set this value to less than the HELLO interval because convergence will not occur.

The negative form of this command, no ip ospf dead-interval, removes the configured time-seconds value and returns this to its default value of 40 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If ip ospf dead-interval is not specified, it defaults to the value specified in "area dead-interval" then the global "dead-interval". If neither of these is specified, however, then it is the same as if the user had specified the following:

(config-if)# ip ospf dead-interval 40

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a dead-interval of 80 seconds in area 1.2.3.4, and a dead-interval of 60 seconds on interface fxp1.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 dead-interval 80

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf dead-interval 60

(config-if)# exit

(config)#

See Also

"dead-interval"

ip ospf enable

Name

ip ospf enable - enables OSPF on an interface

Syntax

ip ospf enable

no ip ospf enable

Mode

Interface Configuration

Parameters

none

Description

The ip ospf enable command specifies to run OSPF on an interface.

Default

By default, OSPF runs on configured interfaces. Therefore, if ip ospf enable is not specified, it is the same as if the user had specified the following:

(config-if)# ip ospf enable

Command History

NGC 2.2 - This command was introduced.

Examples

The following example disables interface fxp1.

(config)# interface fxp1

(config-if)# no ip ospf enable

(config-if)# exit

(config)#

ip ospf hello-interval

Name

ip ospf hello-interval - specifies the length of time in seconds between hello packets that the router sends on the interface

Syntax

ip ospf hello-interval time-seconds

no ip ospf hello-interval time-seconds?

Mode

Interface Configuration

Parameters

time-seconds - an integer between 1 and 65535, inclusive, specifying an amount of time in seconds

Description

Use the ip ospf hello-interval command to specify the number of seconds between Hello packets sent by the router on this interface. This command overrides the interval configured in the equivalent global and area commands. (See "hello-interval" and "area hello-interval".)

A general rule for configuring this value is that it should be equal to one-fourth the dead interval. (See "ip ospf dead-interval".) This value should never be less than the dead interval value.

The negative form of this command, no ip ospf hello-interval, removes the configured time-seconds value. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If ip ospf hello-interval is not specified, it defaults to the value specified in "area hello-interval" then in the global "hello-interval". If neither the area nor global hello interval is specified, however, then it is the same as if the user had specified the following:

(config-if)# ip ospf hello-interval 10

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a hello interval of 20 seconds in area 1.2.3.4, and a hello interval of 15 seconds on interface fxp1.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 hello-interval 20

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf hello-interval 15

(config-if)# exit

(config)#

See Also

"hello-interval"

ip ospf neighbor

Name

ip ospf neighbor - specifies neighboring routes, and specifies whether those routes are eligible to become the designated router (DR)

Syntax

ip ospf neighbor ip_address [eligible]?

no ip ospf neighbor ip_address [eligible]?

Mode

Interface Configuration

Parameters

ip_address - a valid IPv4 address specified in dotted-quad notation

eligible - optionally specify whether the indicated address is eligible to become the DR

Description

The negative form of this command, no ip ospf neighbor, removes the configured neighbors.

Default

OSPF neighbors are not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example specifies that host 10.1.1.1 is eligible to become a DR.

(config)# interface fxp1

(config-if)# ip ospf neighbor 10.1.1.1 eligible

(config-if)# exit

(config)#

ip ospf network

Name

ip ospf network - specifies a either a nonbroadcast interface on an NBMA medium or a point-to-multipoint interface

Syntax

ip ospf network [ point-to-multipoint | nonbroadcast ]

no ip ospf network [ point-to-multipoint | nonbroadcast ]

Mode

Interface Configuration

Parameters

nonbroadcast - specifies a nonbroadcast interface on an NBMA medium

point-to-multipoint - specifies a point-to-multipoint interface

Description

Use the ip ospf network command to specify either a nonbroadcast or point-to-point interface. Because an OSPF broadcast medium must support IP multicasting, a broadcast-capable medium that does not support IP multicasting must be configured as a nonbroadcast interface. This includes the loopback interface on many operating systems.

Default

The default mode is broadcast/point-to-point; therefore this command is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures interface lo1 as a nonbroadcast interface.

(config)# interface lo1

(config-if)# ip ospf network nonbroadcast

(config-if)# exit

(config)#

ip ospf no-multicast

Name

ip ospf no-multicast - disables multicast on a specified interface

Syntax

ip ospf no-multicast

no ip ospf no-multicast

Mode

Interface Configuration

Parameters

none

Description

The ip ospf no-multicast command explicitly disables multicast on a specified interface. The negative form of this command, no ip ospf no-multicast, re-enables multicast on an interface.

Default

By default, interfaces are multicast interfaces. Therefore, if ip ospf no-multicast is not specified, it is the same as if the user had specified the following:

(config-if)# no ip ospf no-multicast

Command History

NGC 2.2 - This command was introduced.

Examples

The following example disables multicast on interface fxp2.

(config)# interface fxp2

(config-if)# ip ospf no-multicast

(config-if)# exit

(config)#

ip ospf passive-interface

Name

ip ospf passive-interface - disables reception and transmission on an interface

Syntax

ip ospf passive-interface

no ip ospf passive-interface

Mode

Interface Configuration

Parameters

none

Description

The negative form of this command, no ip ospf passive-interface, re-enables reception and transmission on the interface.

Default

If ip ospf passive-interface is not specified, it is the same as if the user had specified the following:

(config-if)# no ip ospf passive-interface

Command History

NGC 2.2 - This command was introduced.

Examples

The following example specifies to not send or receive packets on interface fxp2.

(config)# interface fxp2

(config-if)# ip ospf passive-interface

(config-if)# exit

(config)#

ip ospf poll-interval

Name

ip ospf poll-interval - specifies the length of time, in seconds, between OSPF packets that the router send before adjacency is established with a neighbor

Syntax

ip ospf poll-interval time-seconds

no ip ospf poll-interval time-seconds?

Mode

Interface Configuration

Parameters

time-seconds - the length of time in seconds, specified as an integer between 1 and 65535, inclusive

Description

The ip ospf poll-interval command specifies the length of time, in seconds, between OSPF packets that the router sends before adjacency is established with a neighbor. Utilizing this command reduces network overhead in cases where a router may have a neighbor on a given interface at the expense of initial convergence time.

The negative form of this command, no ip ospf poll-interval, removes the configured time-seconds value and returns this to its default value of 120 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If ip ospf poll-interval is not specified, it is the same as if the user had specified the following:

(config-if)# ip ospf poll-interval 120

Command History

NGC 2.2 - This command was introduced.

Examples

The following configures the poll-interval for interface fxp0 to be 100 seconds.

(config)# interface fxp0

(config-if)# ip ospf poll-interval 100

(config-if)# exit

(config)#

See Also

"poll-interval"

ip ospf priority

Name

ip ospf priority - specifies the priority for becoming the designated router (DR)

Syntax

ip ospf priority level

no ip ospf priority level?

Mode

Interface Configuration

Parameters

level - a priority number between 0 and 255, inclusive, for becoming a DR

Description

The ip ospf priority command specifies the priority on this interface for becoming the DR. This priority overrides any that is configured at the global or area levels. (See "priority" and "area priority".) When more than one router attached to a network attempts to become the DR, the one with the highest priority wins. If the competing routers have the same priority, the one with the highest router ID becomes the DR. The router coming in second in the election becomes the backup DR. A router with a priority set to 0 is ineligible to become the DR.

The negative form of this command, no ip ospf priority, removes the configured priority. Note: Specifying a value for level in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Note: This command applies only to broadcast or NBMA media.

Default

If the ip ospf priority command is not specified, then this value defaults to the configured area or global value, respectively. If neither of those is configured, then this value defaults to the following:

(config-if)# ip ospf priority 1

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures an area priority of 10. It also configures the priority for interface fxp1 to be 5.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 priority 10

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf priority 5

(config-if)# exit

(config)#

See Also

"priority"

"area priority"

ip ospf retransmit-interval

Name

ip ospf retransmit-interval - specifies the number of seconds between link state advertisement (LSA) retransmissions for adjacencies

Syntax

ip ospf retransmit-interval time-seconds

no ip ospf retransmit-interval time-seconds?

Mode

Interface Configuration

Parameters

time-seconds - the length of time in seconds, between 1 and 65535, inclusive specified as an integer

Description

The ip ospf retransmit-interval command sets the default for the number of seconds between LSA retransmissions for adjacencies. If a Link State Protocol (LSP) is not acknowledged within the number of seconds specified here, it is re-sent.

This command overrides any configured in the global or area levels. (See "retransmit-interval" and "area retransmit-interval".)

The negative form of this command, no ip ospf retransmit-interval, removes the configured retransmit value. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If the ip ospf retransmit-interval command is not specified, then this value defaults to the configured area or global value, respectively. If neither of those is configured, then this value defaults to the following:

(config-if)# ip ospf retransmit-interval 5

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the retransmit interval for area 1.2.3.4 to be 10 seconds. This value is then overridden in interface fxp1, where it is configured to be 7 seconds.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 retransmit-interval 10

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf retransmit-interval 7

(config-if)# exit

(config)#

See Also

ip ospf traffic-eng administrative-weight

Name

ip ospf traffic-eng administrative-weight - sets the cost of the interface for Traffic Engineering purposes

Syntax

ip ospf traffic-eng administrative-weight number

no ip ospf traffic-eng administrative-weight number?

Mode

Interface Configuration

Parameters

number - an integer from 1 to 65535, inclusive

Description

Use the ip ospf traffic-eng administrative-weight command to configure the cost of the interface for Traffic Engineering purposes. This cost can be different than the normal OSPF interface cost. The negative form of this command, no ip ospf traffic-eng administrative-weight, removes the configured number value.

Notes:

Specifying a value for number in the no form has no effect on the configuration. Thus, it is displayed above as optional.
Traffic engineering must be enabled on the router before this command will take effect. See "enable-te".

Default

This command is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a traffic engineering cost of 6 on interface fxp2.

(config)# router ospf 1

(config-router-ospf)# enable-te

(config-router-ospf)# exit

(config)# interface fxp2

(config-if)# ip ospf traffic-eng administrative-weight 6

See Also

ip ospf traffic-eng attribute-flags

Name

ip ospf traffic-eng attribute-flags - sets the OSPF Traffic Engineering attributes for the interface

Syntax

ip ospf traffic-eng attribute-flags number

no ip ospf traffic-eng attribute-flags number?

Mode

Interface Configuration

Parameters

number - an integer from 1 to 4,294,967,295, inclusive

Description

Use the ip ospf traffic-eng attribute-flags command to sets the OSPF Traffic Engineering attributes for the interface. These flags can be used to indicate which link groups (or "colors") are present on the interface. The negative form of this command, no ip ospf traffic-eng attribute-flags, removes the configured number value.

Notes:

Specifying a value for number in the no form has no effect on the configuration. Thus, it is displayed above as optional.
Traffic engineering must be enabled on the router before this command will take effect. See "enable-te".

Default

This command is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a traffic engineering attribute flag of 1 on interface fxp2.

(config)# router ospf 1

(config-router-ospf)# enable-te

(config-router-ospf)# exit

(config)# interface fxp2

(config-if)# ip ospf traffic-eng attribute-flags 1

See Also

ip ospf traffic-eng bandwidth

Name

ip ospf traffic-eng bandwidth - sets the bandwidth of the interface

Syntax

ip ospf traffic-eng bandwidth kbps

no ip ospf traffic-eng bandwidth kbps

Mode

Interface Configuration

Parameters

kbps - an integer from 1 to 65535, inclusive, specifying a number of kilobytes per second

Description

The ip ospf traffic-eng bandwidth command configures the bandwidth of the interface for Traffic Engineering information distributed within the OSPF domain. The negative form of this command, no ip ospf traffic-eng bandwidth, removes the configured kbps value.

Notes:

Specifying a value for kbps in the no form has no effect on the configuration. Thus, it is displayed above as optional.
Traffic engineering must be enabled on the router before this command will take effect. See "enable-te".

Default

This command is not explicitly configured by default.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures a traffic engineering bandwidth of 1000 kbps for interface fxp2.

(config)# router ospf 1

(config-router-ospf)# enable-te

(config-router-ospf)# exit

(config)# interface fxp2

(config-if)# ip ospf traffic-eng bandwidth 1000

See Also

ip ospf transmit-delay

Name

ip ospf transmit-delay - specifies the number of seconds required to transmit a link state update

Syntax

ip ospf transmit-delay time-seconds

no ip ospf transmit-delay time-seconds?

Mode

Interface Configuration

Parameters

time-seconds - the length of time in seconds, between 1 and 65535, inclusive specified as an integer

Description

The ip ospf transmit-delay command sets the estimated number of seconds required to transmit a link state update. This command takes into account transmission and propagation delays and must be greater than 0. This command overrides any given at the global or area levels ("transmit-delay" and "area transmit-delay").

The negative form of this command, no ip ospf transmit-delay, removes the configured time-seconds value. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If ip ospf transmit-delay is not specified, then this value defaults to the configured area or global value, respectively. If neither of those is configured, then this value defaults to the following:

(config-if)# ip ospf transmit-delay 1

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures the transmit-delay for area 1.2.3.4 to be 10 seconds. This value is then overridden on interface fxp1, where it is configured to be 5 seconds.

(config)# router ospf 1

(config-router-ospf)# area 1.2.3.4 transmit-delay 10

(config-router-ospf)# exit

(config)# interface fxp1

(config-if)# ip ospf transmit-delay 5

(config-if)# exit

(config)#

See Also