[isp-bgp] Re: iBGP session across non-BGP routers

["Teodor Georgiev" <teodor@...]

----- Original Message -----
From: "Scott Ocken" <sgocken@...>
To: <isp-bgp@isp-bgp.com>
Sent: Tuesday, January 07, 2003 4:32 PM
Subject: [isp-bgp] iBGP session across non-BGP routers


> I am trying to get an iBGP session between two cisco 7206 routers that
have some non-BGP routers between them.  The session shows active, but no
messages are send back and forth between the two ciscos.
>

Any State other than "Established" means that you do not have a peering
session with the other side. Before setting up a BGP peering session always
try
to reach the other neighour peer address with a ping or a traceroute.

> Network Diag:
>
>       dr-brief                                        Bulma
>      --------      -----------      -----------       --------
>      | 7206 |      | Wireless |     | Wireless |      | 7206 |
>      eBGP-|      RIP|------| router   |-----| Router   |------|RIP
|-eBGP
>      | BGP  |      | RIP      |     | RIP      |      | BGP  |
>      --------      -----------      -----------       --------
>
> The Wireless Routers can only support static and RIP routes.
>
> The iBGP session config for both ciscos:
>
>
> dr-brief:
>
>  neighbor 69.5.128.254 remote-as 26793
>  neighbor 69.5.128.254 description Link to Bulma
>  neighbor 69.5.128.254 ebgp-multihop 10
>  neighbor 69.5.128.254 version 4
>  neighbor 69.5.128.254 next-hop-self

remove the "next-hop-self" attribute on both the peers. This should be used
only in NBMA (non-broadcast multiaccess) networks like frame-relay or
X.25. Since you use wireless, this definitely is not needed.

If the Linksys Wireless Access Points use RIPv1 - turn it off, it will not
help you at all, just will create a nasty mess. Use static routes then.
If it is RIPv2 - you can use it freely, even to run RIPv2 on the Cisco's.

>
> bulma:
>
>  neighbor 69.5.128.253 remote-as 26793
>  neighbor 69.5.128.253 description Link to Dr Brief
>  neighbor 69.5.128.253 ebgp-multihop 10
>  neighbor 69.5.128.253 version 4
>  neighbor 69.5.128.253 next-hop-self
>
> I tryed the ebgp-multihop 10 to see if i could make connect through the
wireless routers.

it will not work, because the router will "smell" the IBGP peer session
because of the same AS number in the remote-as statement.