ISP customer assignments

Tue Oct 13 23:26:20 UTC 2009

Once upon a time, Michael Dillon <wavetossed at googlemail.com> said:
> > How many addresses do you like on point-to-point circuits?
> 
> That will become one of those great interview questions, because anyone who says
> something like "a /127" or "a /64" will be someone that you probably
> don't want to hire.
> 
> The right answer is to explain that there are some issues surrounding
> the choice of
> addressing on point-to-point circuits and there has even been an RFC
> published discussing
> these issues, RFC 3627 <http://www.ietf.org/rfc/rfc3627.txt>

Still learning here, so please go easy...

I read the above, and I see section 4 item 3 says:

   The author feels that if /64 cannot be used, /112, reserving the last
   16 bits for node identifiers, has probably the least amount of
   drawbacks (also see section 3).

I guess I'm missing something; what in section 3 is this referring to?
I can understand /64 or /126 (or maybe /124 if you were going to
delegate reverse DNS?), but why /112 and "16 bits for node identifiers"
on a point-to-point link?
-- 
Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.