Re: google ipv6 routes via cogent

[Niels Bakker <niels=nanog () bakker net>]

* aaron1 () gvtc com (Aaron Gould) [Thu 02 Mar 2017, 20:52 CET]:
> Yes, thanks, I am going to do that.  But, is there a middle ground 
> between being default only and full routes ?  Like is it 
> advantageous for me to ask for partial routes (like their routes and 
> direct peers and default route) ?  This way I don't have millions of 
> routes but I guess only a few hundred thousand or less? Let me know 
> please.

You should ask for full routes from all your providers + a default.

Then you write per-upstream import policies to permit or deny specific 
subsets of the prefixes they announce to you.  For example, you could 
accept all prefixes from Cogent and your other upstreams tagged with a 
BGP community indicating they're from customers, and accept default 
from all except Cogent to take care of the rest of the traffic while 
still pretty much sending traffic to downstream customers to their 
respective upstream.  (Or you can accept default from all but also 
import networks with whom Cogent has no direct relationship from your 
other upstreams; but that's less failsafe.)

Depending on what router hardware you have and what upstreams, you may 
have to filter out additional prefixes to not overflow its FIB.


        -- Niels.