IPv6 Prefix announcing

Kate Gerry kate at quadranet.com
Tue Apr 26 16:39:02 UTC 2011

Funny enough, some carriers actually require the 'smallest' as being /32... :(

-----Original Message-----
From: Justin M. Streiner [mailto:streiner at cluebyfour.org] 
Sent: Tuesday, April 26, 2011 9:34 AM
To: nanog at nanog.org
Subject: Re: IPv6 Prefix announcing

On Tue, 26 Apr 2011, Nick Olsen wrote:

> I've always been under the impression its best practice to only 
> announce prefixes of a /24 and above when it comes to IPv4 and BGP.
> I was wondering if something similar had been agreed upon regarding IPv6.
> And if That's the case, What's the magic number? /32? /48? /64?

You're likely to get different answers to this, but the 'magic number' 
appears to be /48.  Looking in the v6 BGP table, you will likely find smaller prefixes than that, but a number of the major carriers seem to be settling on /48 as the smallest prefix they will accept.  /48 is also the smallest block most of the RIRs will assign to end-users.


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