From: Nigel Taylor (nigel_taylor@xxxxxxxxxxx)
Date: Sun Dec 31 2000 - 15:24:56 GMT-3
Hey Julie Ann,
You pretty much answered this yourself. The
specifics on when and
why you would use network statements is done from a failover standpoint. Of
course,
the network(s) that are defined under the BGP process are now statically
defined to
BGP and guarantee that they are advertised to eBGP peers. As well, if
internal routing
fails and there is no route in the RIB for these network(s) they will not to
be advertise
because one of two requirements for BGP will not have been met.
The big issue-spotting technique to here is to know which networks are being
redistributed into BGP and which is not. With the keys words listing the
specific
routes as "INCOMPLETE" or "IGP".
Nigel.
----- Original Message -----
From: Connary, Julie Ann <jconnary@cisco.com>
To: <ccielab@groupstudy.com>
Sent: Sunday, December 31, 2000 10:58 AM
Subject: network statement in bgp - best practice question
> Hi All,
>
> I'm working on some labs and I am doing this one lab using first
> redistribution and second
> network statements under bgp.
>
> My question is if you have 3 ibgp neighbors in AS 200. Router 1 is EBGP
> peered to AS100. Router 2 and
> 3 are EBGP peered to AS300. Since Router 1, 2 and 3 are in the same AS,
> running an IGP, so they
> have knowledge of all internal routes, is it best to put a network
> statement for the local network numbers in
> all 3 BGP routers or just one?
>
> I am using network 10.x.x.x, so I put in router 2 network statements for
> all the particular
> subnets and then an aggregate-summary address (I guess, I could just have
> left auto-summary on also).
> I noticed that routers 1 and 3 get
> the route via IBGP, since they have routes to the 10.x.x.x network it
> becomes a best route
> and they advertise it via EBGP.
>
> Any rules of thumb? Perhaps it is best to put it in all border routers
> incase internal routing fails?
>
> Julie Ann
> ------------------------------------------------------------------------
> Julie Ann Connary
> | | Network Consulting Engineer
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>
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