Using /31 for router links

Tony Varriale tvarriale at
Sat Jan 23 01:23:15 UTC 2010

Shouldn't be any's 2010 :)

And, your IP allocation utilization will love you.

----- Original Message ----- 
From: "Seth Mattinen" <sethm at>
To: "nanOG list" <nanog at>
Sent: Friday, January 22, 2010 6:08 PM
Subject: Using /31 for router links

> In the past I've always used /30's for PTP connection subnets out of old 
> habit (i.e. Ethernet that won't take unnumbered) but now I'm considering 
> switching to /31's in order to stretch my IPv4 space further. Has anyone 
> else does this? Good? Bad? Based on the bit of testing I've done this 
> shouldn't be a problem since it's only between routers.
> ~Seth

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