Equal Cost Path Splitting

You can configure the maximal number of equal-cost paths that will be used when there is more than one equal-cost path to a destination.

You can specify a value for the maximal number of equal-cost paths to be used when there is more than one equal-cost path to a destination.

Only OSPF, BGP, and Static routes are able to use paths/routes with more than one "nexthop".

The "next hop" algorithm that is used for forwarding when there is more than one "next hop" to a destination is Source/Destination hash.

A hash function is performed on the source and destination IP address of each packet that is forwarded to a multipath destination.

This result is used to determine which next hop to use.

Important: In a Cluster Two or more Security Gateways that work together in a redundant configuration - High Availability, or Load Sharing., you must configure all the Cluster Members in the same way. If you change the current number of equal cost paths, the routing system reinstalls all routes. This causes a traffic outage.

Configuring Equal Cost Path Splitting in Gaia Portal

1. From the left navigation tree, click Advanced Routing > Routing Options.

2. In the Equal Cost Multipath section:

   1. In the Maximum Paths field, enter the applicable number of equal cost paths.

      Range: 1-8

      Default: 8

   2. In the Path Selection Algorithm field, select the applicable algorithm:

      • 2-tuple Hash - Based on the hash of Source and Destination (this is the default)

      • 5-tuple Hash - Based on the hash of Source, Destination, Source Port, Destination Port, and Protocol

3. In the Routing Options section (at the top), click Apply.

Configuring Equal Cost Path Splitting in Gaia Clish

1. Configure the applicable number of equal cost paths:

   set max-path-splits {<1-8> | default}

   Range: 1-8

   Default: 8

2. Configure the applicable path selection algorithm:

   set router-options ecmp-nexthop-selection {2-tuple-hash | 5-tuple-hash}

   • "2-tuple-hash" - Based on the hash of Source and Destination (this is the default)

   • "5-tuple-hash" - Based on the hash of Source, Destination, Source Port, Destination Port, and Protocol

3. Save the configuration:

   save config

4. Examine the configuration:

   • To see the configured number of equal cost paths:

     Run in Gaia Clish The name of the default command line shell in Check Point Gaia operating system. This is a restricted shell (role-based administration controls the number of commands available in the shell).

     show configuration max-path-splits

   • To see the configured path selection algorithm:

     Run in the Expert mode:

     cat /proc/sys/net/ipv4/fib_multipath_hash_policy

     The returned value:

     • 0 means the "2-tuple Hash" is configured

     • 1 means the "5-tuple Hash" is configured