In message <199504241414.AA14108@zed.isi.edu>, bmanning@ISI.EDU writes:
| This sounds a lot like the slippery slope of static routing being the most | stable, so we should encourage its use Internet wide. I -know- Karl D. | (and others that depend on dynamic routing for alternate provider fallback) | will kick at this.
Why? What we have been arguing for has been limiting the scope of dynamic routing only to places where participating in global dynamic routing makes sense.
So it does not make sense for IBM or Sony to run dynamic routing in their internal networks?!?
The border router does aggregation outbound and points the aggregates at Null 0 with a high metric.
True.
This is for cases in which there is no other router participating within the customer iBGP mesh, and where there are N (N>=1) upstream providers, and where dynamic routing must take place within the ISP's routing domain for various reasons (portable dialup links, links that are time-sensitive, etc.)
The assumption in this case is a common egress point.
The iBGP box should do aggregation and have static routes pointing to Null0 for all nets it announces to the two edge routers.
Again, a common egress point is assumed and to differeniate policy by provider will involve netlists.
A more complex case is one like this:
Provider X Provider Y Peers A, B, Z | | | +--------+ +--------+ +---------+ | | | | | | +--------+ +--------+ +---------+ \ | / (a bunch of iBGP-talking routers)
at this point people are building something akin to what NSPs do. .............. Step 2 is to do the _same_ aggregation and high-metric routing to Null 0 on all the border boxes (the three shown above) so that a consistent picture of this small-i internet is presented to the outsides world.
The assumption here is that there is a consistant policy from this ISP to all its peers. This may not be true. (I am working at a site which is an existance proof)
I'd detail several more steps but my fingers tell me they want to go on to the next message.
No problem... --bill