nanog mailing list archives

Re: Consistent routing policy?


From: Mark Tinka <mark.tinka () seacom mu>
Date: Mon, 16 Sep 2019 15:05:08 +0200



On 16/Sep/19 14:47, Ben Logan wrote:
Thanks, Mark.  So the discrepancy between what's being advertised (/21
vs /22) shouldn't cause any issues?  That's the part I got a bit
confused about.  I don't see how it would, but I wanted to make sure.

Longest match always wins... so provided your /22's are in the global
table, traffic will follow the path toward them before the /21 is preferred.

So, for example, if the upstream to whom you are sending the /21 doesn't
do anything about how they learn the /22 from another source, (for their
network) they will also send traffic back to you via the /22 path. This
may or may not be preferred by you, or them. I suppose that's the main
thing to think about.

Mark.


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