MAC Addresses and Bit Conventions

MAC Addresses

MAC addresses divide into three types:

BMAC. A MAC address assigned to all interfaces with the "BPEthX" naming convention. Unique per member. It does not rely on the interface index number.
VMAC. A MAC address assigned to all interfaces with "ethX-YZ" naming convention. Unique per Chassis, it does not rely on the interface index number.
SMAC. A MAC address assigned to Sync interfaces. Unique per member, it does not rely on the interface index number.

Bit Conventions

BMAC

1 - 1 bit stating if this address is BMAC/SMAC(0) or VMAC(1) to avoid possible collision with VMAC space.
2,...,8 - 7 bits that state the member ID (starting from 1) - limited to 127 members
9,...,13 - zero bits.
14 - 1 bit stating if this address is BMAC(0) or SMAC(1) to avoid possible collision with SMAC space
15,16 - 2 bits that state the absolute interface number (taken from interface name: i.e. in BPEthX, X is the interface number - limited to four interfaces.)

SMAC

1 - 1 bit stating if this address is BMAC/SMAC(0) or VMAC(1) to avoid possible collision with VMAC space
2,...,8 - 7 bits that state the member ID (starting from 1) - limited to 127 members
9 - 1 bit stating whether it is Sync1(0) or Sync2(1)
9,...,13 - zero bits
14 - 1 bit stating if this address is BMAC(0) or SMAC(1) to avoid possible collision with BMAC space
15 - Zero bit
16 - 1 bit stating whether it is Sync1(0) or Sync2(1)

VMAC

1 - 1 bit stating if this address is BMAC/SMAC(0) or VMAC(1) to avoid possible collision with BMAC/SMAC space
2,...,3 - 2 bits to indicate Chassis id (starting from 0) - limited to 4 boxes
4,...,8 - 5 bits to indicate switch number - limited to 32 switches
9,...,16 - 8 bits to indicate port number - limited to 256 ports per switch.