As I sat in the auditorium listening to the speakers at the
NANOG meeting Thursday and Friday, a realization came to me.
Almost every speaker there who happened to talk about the problems with
space and CIDR and what-not said "renumbering is a fact of life", or
"renumbering is a simple method to solving these problems".
While contemplating this, I realized that every speaker who said
something along these lines really hasn't done massive renumbering
to fulfill CIDR plans--they either have this HUGE block (i.e., major
provider like SprintLink) that just needs to be aggregated on out-bound or
aren't involved in the direct operation of NSP/ISP's.
I've seen a specialty provider renumber about 15 class C's _twice_, the
first because he changed providers and they urged him to CIDRize. He then
had to change again when the first provider didn't live up to the contractual
obligations. Because of a lack of planning on his part, he lost 20% of
his customer space during/after these renumberings--customers don't want to
put up with problems such as a) applications which compute the IP address
into an equation with the license number, b) problems with _all_ parameters
not being changed in terminal servers and hosts, c) DNS problems with
off-site backup servers, and a few others that just generally made his
customers not happy.
(Keep in mind that "a)" above generally requires you to purchase new
licenses from the software manufacturer.)
The problem, you ask? I don't see very many resources available which
help ISP's to renumber more easily--time line planners, reminder lists
with commonly-missed parameters, etc.
I realize that renumbering is a fact of life--my last post, however,
shows my true feelings regarding most pre-CIDR blocks; that their
providers should be willing to allow customers to keep using the space they
allocated in the pre-CIDR days.
If there are these renumbering resources available, make sure that the small
and big providers alike are making them available to the customers who are
willing to attempt a re-number. Make sure the customer service of the
provider is willing to deal with the complexities of renumbering (and
keep in mind it _IS_ a very complex project--EVERYTHING from IP addresses
to static routes to applications which are hard-coded). Unfortunately, the ISP
that I saw change providers didn't have this help at their fingertips--they
could have potentially saved almost all of the customers they lost.
My thanks go out to everyone who made this NANOG one of the best--keep up
the good work!