From: Brad Hedlund (BHedlund@xxxxxxxxxxxxxxxxxxx)
Date: Thu Feb 03 2000 - 19:11:44 GMT-3
Greg,
PPP, by design, installs a host route for its peering router.
Do a show ip route on R3 and you will see a /32 route for R2.
This route uses the interface as a next-hop, thus it is a connected route
(C).
When you say redistribute connected, this host route gets pulled in as well.
Brad Hedlund
CCIE #5530
Network Guidance Co.
> -----Original Message-----
> From: Greg Schwimer [mailto:schwim@speedchoice.com]
> Sent: Thursday, February 03, 2000 3:17 PM
> To: CCIE Lab (E-mail)
> Subject: IBGP, PPP, Ethernet, and redistribute connected
>
>
> Does anyone know why this is happening?
>
>
> R2 R5
> ! !
> \ /
> \ /
> R3
>
>
> R2 and R5 are border routers connected to separate AS's and
> running EBGP to
> them. They are both peered via IBGP with R3, but not each other. The
> connection between R2 and R3 is PPP, and between R5 and R3 is
> ethernet.
>
> When I redistribute connected to BGP on R3, it takes both the
> subnet between
> R2 and R3 as well as the interface address of R2 on that subnet and
> redistributes it. This does not happen between R5 and R3.
> R5 learns this
> interface route from R3 and forwards it out via EBGP.
>
> Why is R3 redistributing the interface address? Here's what
> the BGP table
> on R3 looks like relating to the PPP link:
>
> *> 172.16.23.0/24 0.0.0.0 0 32768 ?
> *> 172.16.23.2/32 0.0.0.0 0 32768 ?
>
> Here is what it looks like on R5:
>
> *>i172.16.23.0/24 172.16.35.3 0 100 0 ?
> *>i172.16.23.2/32 172.16.35.3 0 100 0 ?
>
>
> My BGP config on R3 looks like this:
>
> router bgp 400
> no synchronization
> redistribute connected
> neighbor 172.16.23.2 remote-as 400 <- to R2
> neighbor 172.16.35.5 remote-as 400 <- to R5
> no auto-summary
>
> Any ideas? Is this because the link between R2 and R3 is
> point-to-point?
>
> Thanks!
> Greg
>
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