Re: BGP synchronization problem

From: Bob Sinclair (bsin@cox.net)
Date: Sun May 01 2005 - 10:04:10 GMT-3


KC,

Interesting IBGP issues usually involve next-hop reachability, full mesh
peering issues, or synchronization problems. Can you send the output from
"show ip bgp 3.0.0.0" on R2? Do the OSPF and BGP RIDs match on R3?

Bob Sinclair
CCIE #10427, CCSI 30427, CISSP
www.netmasterclass.net

  ----- Original Message -----
  From: k c
  To: ccielab@groupstudy.com
  Sent: Sunday, May 01, 2005 12:34 AM
  Subject: BGP synchronization problem

  Hi Group,

  R3 (AS64600, RR) ----R2 (AS64600, RR client)----R1(AS100)
  R3 (sync must be on) annouce 3.0.0.0/8 in bgp and ospf to R2

  In R2, prefix 3.0.0.0/8 cannot annouce to R1.
  *May 1 18:46:08.528: BGP(0): no valid path for 3.0.0.0/8

  However, 3.0.0.0/8 is received on R2 via ospf. Why "invalid path" appearred
in debug message? Any hints?

  Routing entry for 3.0.0.0/8
    Known via "ospf 1", distance 110, metric 65, type inter area
    Last update from 172.16.123.3 on Serial4/0, 00:15:55 ago
    Routing Descriptor Blocks:
    * 172.16.123.3, from 192.168.99.1, 00:15:55 ago, via Serial4/0
        Route metric is 65, traffic share count is 1

  R2#sh ip bgp
  BGP table version is 21, local router ID is 2.2.2.2
  Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
                r RIB-failure, S Stale
  Origin codes: i - IGP, e - EGP, ? - incomplete
     Network Next Hop Metric LocPrf Weight Path
  * i3.0.0.0 172.16.123.3 0 100 0 i
  *> 172.16.77.0/24 172.16.123.1 0 100 700 i
  *> 192.168.100.0/22 172.16.123.1 0 0 100 700 ?
  *> 192.168.104.0 172.16.123.1 0 100 700 ?
  *> 192.168.105.0 172.16.123.1 0 100 700 ?

  In R2, bgp syn must on.

  router bgp 64600
   synchronization
   bgp router-id 2.2.2.2
   bgp log-neighbor-changes
   neighbor 172.16.123.1 remote-as 100
   neighbor 172.16.123.3 remote-as 64600
   no auto-summary

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