nanog mailing list archives

Re: v6 subnet size for DSL & leased line customers


From: Chris Adams <cmadams () hiwaay net>
Date: Fri, 21 Dec 2007 11:20:41 -0600


Once upon a time, TJ <trejrco () tjevans net> said:
Short answer - no spec for it.
      ARIN breaks it at /56, as a nod towards maybe a /48 for everyone is
a bit much.

On ARIN's site:

 The following guidelines may be useful (but they are only guidelines):

    * /64 when it is known that one and only one subnet is needed
    * /56 for small sites, those expected to need only a few subnets
      over the next 5 years.
    * /48 for larger sites

 For end sites to whom reverse DNS will be delegated, the LIR/ISP should
 consider making an assignment on a nibble (4-bit) boundary to simplify
 reverse lookup delegation.

So, the guidelines are on 8 bit boundaries, but then right below they
also suggest making assignments on 4 bit boundaries (and it is all "only
guidelines").

-- 
Chris Adams <cmadams () hiwaay net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.


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