using IPv6 address block across multiple locations

Justin M. Streiner streiner at
Mon Oct 31 14:42:33 UTC 2011

On Mon, 31 Oct 2011, Dmitry Cherkasov wrote:

> The problem we ran across is that ISP in US does not wish to accept
> prefixes longer then /48 from us.
> Need your advice: is this normal to distribute /48 by /56 parts across
> locations or should we obtain separate /48 for each of them? Or maybe
> we need /32 that can be split into multiple /48? Anyway we are not ISP
> so /48 looks quite reasonable and sufficient for all our needs.

Think of a /48 the same way you'd use a /24 of IPv4 space in a multi-homed 
design.  /48 is the smallest v6 block that you can reasonably expect to be 
globally reachable.  Many providers will not accept anything smaller, 
unless it's from one of their own blocks, in which case it will likely get 
aggregated into their larger prefix.


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