v6 subnet size for DSL & leased line customers

Robert E. Seastrom rs at seastrom.com
Fri Dec 21 19:12:01 UTC 2007


Chris Adams <cmadams at hiwaay.net> writes:

> Once upon a time, Owen DeLong <owen at delong.com> said:
>> I think it makes sense to assign as follows:
>> 
>> /64 for the average current home user.
>> /56 for any home user that wants more than one subnet
>> /48 for any home user that can show need.
>
> Dumb question alert: why the 8 bit boundary?  That makes sense for IPv4,
> where reverse DNS delegation is cumbersome on non-octet boundaries, but
> IPv6 reverse DNS can be delegated at the nibble boundary.  Why not
> assign /60, /52, etc.?  A /60 would probably satisfy virtually all home
> users (up to 16 subnets) for example.

IPv6 is supposed to last a whole lot longer than the current horizon
for any of our imaginations, and given the large amount of space in
play it seems prudent to err on the side of giving people more rather
than less so as to avoid having to revisit this issue later.

                                        ---rob





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