RE: 'update-source Loopback0'-BGP question!!

From: Phuong (kieu@hn.vnn.vn)
Date: Sun Aug 03 2003 - 16:23:26 GMT-3


In this case, no way to form the neihgborhood between R1&R2. You could
see their relation stop in ACTIVE state. To become neighbor, they
should be able to establish TCP connection via port 179. As you know, R1
can't reach R2 loopback.

Phuong

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
wwwjjang@chol.com
Sent: Monday, July 28, 2003 10:23 PM
To: ccielab@groupstudy.com
Subject: 'update-source Loopback0'-BGP question!!

This is a diagram

 L0(2.2.2.2/24)-R2-(e0 1.1.1.1/24)--(e0 1.1.1.2)-R1

Assumtion>
-R1 is in AS 1 and R2 is in AS2
-There is no routing protocol in R1 & R2
-There is no static routing in R1 such as "ip route 2.2.2.2/24 1.1.1.1"

Question>

-When you config a EBGP-peers between R1 & R2,
 You have to do configure R2 to use L0-int as the update-source for BGP
 against R1 !!

---------------
My answer
----------------
R1>

router bgp 1
 bgp log-neighbor-changes
 neighbor 2.2.2.2 remote-as 2
 neighbor 2.2.2.2 ebgp-multihop 255

R2>

router bgp 2
 bgp log-neighbor-changes
 neighbor 1.1.1.1 remote-as 1
 neighbor 1.1.1.1 update-source Loopback0 **
 --> the interface for EBGP-Peering with R1 is L0. is right???

==> R1 has no route to the 2.2.2.2/24, The EBGP-Peers Can't
established!!
    How can i make a EBGP-peer between R1 & R2 ???

R1#sh ip bgp summ
BGP router identifier 172.168.70.1, local AS number 1
BGP table version is 1, main routing table version 1

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down
State/PfxRcd
2.2.2.2 4 2 0 0 0 0 0 never Active

R2#sh ip bgp summ
BGP router identifier 2.2.2.2 local AS number 2
BGP table version is 1, main routing table version 1

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down
State/PfxRcd
1.1.1.1 4 1 38 38 0 0 0 00:29:47
Active



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