Solved: Re: vPC Keep Alive IP addresses

dbeattie · ‎06-07-2018

I am about to refresh an environment with about 40 vPC pairs of Nexus 9K. I am considering using the IPv4 Link Local addressing for the keep alive links: RFC 3927 - 169.254.0.0/16. This is because this range is otherwise unusable and unrouteable. Has anyone done this before? Can anyone see any issues with it.

Thanks,

Peter Paluch · ‎06-07-2018

Hello,

As far as vPC is concerned, the 169.254.0.0/16 range is as good as any other, and it will certainly work.

The "unrouteability" of this range, however, is only a recommendation, not something that would be imposed in routers' operating systems and their forwarding hardware by default. Routers will route the packets from and to this address range just like any other packets, depending simply on their routing table contents.

So - certainly no issues with using this range, but at the same time, no specific added security in comparison to any other unicast address range that would be available.

Best regards,
Peter

View solution in original post

Peter Paluch · ‎06-07-2018

Hello,

As far as vPC is concerned, the 169.254.0.0/16 range is as good as any other, and it will certainly work.

The "unrouteability" of this range, however, is only a recommendation, not something that would be imposed in routers' operating systems and their forwarding hardware by default. Routers will route the packets from and to this address range just like any other packets, depending simply on their routing table contents.

So - certainly no issues with using this range, but at the same time, no specific added security in comparison to any other unicast address range that would be available.

Best regards,
Peter