Justin M. Streiner wrote:
On Tue, 9 Oct 2007, Patrick W. Gilmore wrote:
Justin, if Provider A _has_ permission from Provider B to announce a
prefix, do you believe Provider A should be allowed to announce the
prefix?
As long as all of the relevant parties know about it and are OK with it,
that's fine. It's just not my first choice for solving the customer's
multihoming dilemma, that's all :)
jms
Back when I was a NOC monkey (that stopped a month ago), I had exactly
that situation. I had MCI and SBC as upstreams. Before multihoming, my
network was split in two segments, one for each substream. This made
things like DNS interesting.
When I got my ASN, I got agreement from both MCI and SBC to announce my
/21 allocations from them over both upstream circuits. As a result, I
was able to go back to a single inside network, a single pair of DNS
servers, and no more cross-router traffic via the Internet cloud.
I then got my ARIN allocation and went through the Fiscal Quarter From
Hell renumbering everything into the new number block. I dropped MCI
(long story) and lit up Idacomm, but kept SBC link and numbers.
When I left the ISP, my routers had been announcing my suballocation of
SBC space for more than a year. With their permission. Their only
requirement is that I have proper routing objects in a routing registry
so SBC could see that the route I was announcing was valid. (What was
VERY interesting was that I was using the ARIN registry, and SBC was
not. The resulting bru-ha-ha uncovered a synchronization problem that
ARIN had, and that ARIN fixed.)
