Is a /48 still the smallest thing you can route independently?

Randy Carpenter rcarpen at network1.net
Thu Oct 11 21:28:37 UTC 2012


> --- jrhett at netconsonance.com wrote:
> From: Jo Rhett <jrhett at netconsonance.com>
> 
> I've finally convinced $DAYJOB to deploy IPv6.  Justification for the
> IP space is easy, however the truth is that a /64 is more than we
> need in all locations. However the last I heard was that you can't
> effectively announce anything smaller than a /48.  Is this still
> true?
> 
> Is this likely to change in the immediate future, or do I need to ask
> for a /44?
> ----------------------------------------------------
> 
> 
> A /48 is 65536 /64s and a /44 is 16x65536 /64s.  If you
> only need one subnet (1 subnet = 1 /64), why would you
> try to get 16x65536 subnets, rather than the 65536 you
> have in the /48?
> 
> scott


He said it was for multiple sites. Per ARIN policy, the next biggest chunk from a /48 is a /44, so a /44 is what should be asked for. It is perfectly justifiable if you have more than 1 site.

I would not expect anything smaller than a /48 to be allowed in BGP.

A bonus would be that a /44 currently costs the same as a /48 for an enduser, so there really is no drawback from getting the /44, and having enough space to not have to worry about it in the future.

-Randy



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