When the auto-boot ospf flag is used without any options, the NEID is autogenerated from the chassis MAC address. The least significant bytes of the chassis MAC address can be 00 or FF. These values are invalid as least significant bytes of an IP address. SR OS uses the following methods to mitigate these invalid bytes:
For IPv4, the least significant chassis MAC bytes (3 to 5) are used to generate the NEID. The bytes are shift to the left by 2 bits and ‟logical OR”-ed with 01 to generate the least significant 3 bytes of the IPv4 address.
For IPv6, the least significant chassis MAC bytes (2 to 6) are used to generate the NEID. The bytes are shift to the left by 2 bits and ‟logical OR”-ed with 01 to generate the least significant 5 bytes of the IPv6 address.