nanog mailing list archives

RE: IPv6 /48 advertisements


From: Cliff Bowles <cliff.bowles () apollogrp edu>
Date: Wed, 18 Dec 2013 09:40:34 -0700

I had a feeling... thanks for the feedback.

CWB

From: Blake Dunlap [mailto:ikiris () gmail com]
Sent: Wednesday, December 18, 2013 9:32 AM
To: Edward Dore
Cc: Cliff Bowles; nanog () nanog org
Subject: Re: IPv6 /48 advertisements

Regardless of the carriers, you'll find most ASs on the internet only listen to /48 or larger. So even if you get your 
prefixes accepted by your provider, don't assume you can get anywhere, or have your packets not fall in to uRPF 
blackholes randomly without a larger aggregate announcement.
-Blake

On Wed, Dec 18, 2013 at 10:22 AM, Edward Dore <edward.dore () freethought-internet co uk<mailto:edward.dore () 
freethought-internet co uk>> wrote:
If you're talking about announcing each location separately, then RIPE have a couple of useful articles about prefix 
visibility on Ripe Labs:

https://labs.ripe.net/Members/emileaben/ripe-atlas-a-case-study-of-ipv6-48-filtering
https://labs.ripe.net/Members/dbayer/visibility-of-prefix-lengths

Otherwise I guess you'll need to talk to your chosen carrier(s) about aggregating your space for you, which will come 
down to their policies on what routes they will carry internally.

Edward Dore
Freethought Internet

On 18 Dec 2013, at 16:11, Cliff Bowles <cliff.bowles () apollogrp edu<mailto:cliff.bowles () apollogrp edu>> wrote:

I accidentally sent this to nanog-request yesterday. I could use some feedback from anyone that can help, please.

Question: will carriers accept IPv6 advertisements smaller than /48?

Our org was approved a /36 based on number of locations. The bulk of those IPs will be in the data centers. As we 
were chopping up the address space, it was determined that the remote campus locations would be fine with a /60 per 
site. (16 networks of /64). There are usually less than 50 people at the majority of these locations and only about 
10 different functional VLANs (Voice, Data, Local Services, Wireless, Guest Wireless, etc...).

Now, there has been talk about putting an internet link in every campus rather than back hauling it all to the data 
centers via MPLS. However, if we do this, then would we need a /48 per campus? That is massively wasteful, at 65,536 
networks per location.  Is the /48 requirement set in stone? Will any carriers consider longer prefixes?

I know some people are always saying that the old mentality of conserving space needs to go away, but I was bitten by 
that IPv4 issue back in the day and have done a few VLSM network overhauls. I'd rather not massively allocate unless 
it's a requirement.

Thanks in advance.

CWB




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