Point 2 point IPs between ASes

Justin M. Streiner streinerj at gmail.com
Thu Jun 29 12:49:36 CST 2017

On Thu, 29 Jun 2017, William Herrin wrote:

> Heck, I’m gonna do whatever it takes to NOT subnet on bits with my v6
>> deployment.  Hopefully with v6, gone are the days of binary subnetting math.

I hedged my bets when I laid out our v6 space at my previous $dayjob.  We 
used /126s for point-to-point links, but carved out a /64 for each 
point-to-point link in our IPAM system.  That way, if we ever encountered 
a device that wouldn't play nicely with a /126 on a point-to-point link, 
we could just change the mask to /64 (or something else, if the device 
requires a byte or nibble boundary) on the interface and any relevant 
ACLs and not have to re-provision addresses for the link.

I seem to recall that our upstreams generally standardized on /126s for 
point-to-point interconnects to us.  We had one interconnect that was a 
/64, but that also wasn't a point-to-point link.


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