On woensdag, apr 30, 2003, at 18:20 Europe/Amsterdam, Stephen Sprunk
this is an interesting point, but I think it has more to do with
the prefixes are statically bound to customers than the length of
why would giving customers static /64s result in fewer
routes in your IGP than giving them static /48s?
I was suggesting nothing of the sort; just assumed that _if_ you're
going to give a customer something fixed it would be a /48 while a
dynamic /48 doesn't make much sense the way things are now.
IMHO, dialup is a bad example because static IPs per customer are rare;
let's switch to the cable/dsl market.
Standard practice is to connect all customers in a given area (or
in a given period) to a single concentrator via some sort of virtual
(PPPoE, ATM, FR, etc). This concentrator then internally bridges all
these virtual circuits into a single subnet with a single prefix,
one route for N customers.
Ok, I'm not all that familiar with cable/ADSL, but isn't this more
often done by giving each customer a virtual point to point link? In
the case of PPP over ethernet I don't see how it could work otherwise.
Now of course you can then proxy ARP...
OTOH, if you assign a prefix to each customer,
you then have between N+1 and 2N routes for N customers.
Unless you aggregate, of course. For cable/ADSL that shouldn't be a
problem as the customers conveniently stay in the same place. :-) Not
so with dial.
The latter might
be justified if we're truly committed to eliminating NATs, but it
lot more in routes, in administration, and in address waste (assigning
to what is, in nearly all cases, 1-4 hosts).
So we should give them a /126???
I guess a /64 would be enough for most people. You are underestimating
the number of hosts, though: don't forget about IP phones, IP radios
and stuff like that. And I'm not even counting more obscure examples
such as IP refrigirators.