IGP/BGP design question
ml at kenweb.org
Wed Jun 17 20:39:46 CDT 2009
We have three main cities wherein eyeballs live. Currently we have San
Jose and San Francisco traffic egressing in SF, and Los Angeles
egressing in LA. There is one private 2x1gig long haul linking SJC to
LA and a 1x 10gig linking SJC to SF. i.e SF <-10gig-> SJC <-2gig-> LA
Each area is a separate OSPF domain. Static routes define how to reach
the RFC1918 space defined for each area. Currently SF and SJC exchange
their public blocks in iBGP. There isn't an iBGP session between SF and
SJC to LA. We would would like to place our public IP blocks into iBGP
with LA and use the 2gig long haul as a backup path for critical traffic
destined for the Internet.(Only certain prefixes originated from each
egress point will be announced out the opposite egress point;
Appropriately locally-pref down inside our common transit ASN)
Using only one assigned ASN is this a good idea?
Is our IGP setup foobared (I've been mulling around possible changing
the IGP design)? I can think of a problem or two this IGP design might
cause us but it's a huge change on our part if we do it.
The egress points are not DFZs, so if either the 10gig or 2gig link go
down the default route can be taken to reach the public blocks in either
of the three regions.
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