nanog mailing list archives

Re: IPv6 /48 advertisements


From: Chuck Anderson <cra () WPI EDU>
Date: Wed, 18 Dec 2013 11:16:56 -0500

On Wed, Dec 18, 2013 at 09:11:46AM -0700, Cliff Bowles wrote: 
Question: will carriers accept IPv6 advertisements smaller than /48?

Not generally, no.

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?

/48 per site is the standard.

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.

You need to throw out all old thinking in terms of what happened in
IPv4.  Current ARIN policy allows a /48 per site and that is how you
should architect the network.


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