[c-nsp] BGP best path

[Mikisa Richard]

Oliver Boehmer (oboehmer) wrote:

>Mikisa Richard <> wrote on Tuesday, May 02, 2006 3:09 PM:
>
>  
>
>>Hi,
>>
>>Below is bgp output from the same router with  a few seconds interval
>>between. Notice the last two routes. They are not best in the first
>>output but then they are in the second. It keeps doing this, Is there
>>a way I can make this permanently best.
>>    
>>
>
>Please take the output of "show ip bgp 63.103.129.0" a couple of times
>and check why the router is preferring the other path over this one. 
>
>	oli
>
>  
>
aha, comes up as inaccessible for a moment and then becomes accessible 
again ..

BUSH-UPLINK-01#sh ip bgp 63.103.129.0/24
BGP routing table entry for 63.103.129.0/24, version 189382
Paths: (2 available, best #1, table Default-IP-Routing-Table)
Flag: 0x208
  Advertised to non peer-group peers:
  213.248.97.89
  23549
    64.152.195.33 from 217.212.242.2 (217.212.243.253)
      Origin IGP, metric 0, localpref 100, valid, internal, best
  1299 3356 11908 10530 23549
    213.248.97.89 from 213.248.97.89 (80.239.146.12)
      Origin IGP, localpref 100, valid, external
      Dampinfo: penalty 393, flapped 3 times in 00:43:31


BUSH-UPLINK-01#sh ip bgp 63.103.129.0/24
BGP routing table entry for 63.103.129.0/24, version 189467
Paths: (2 available, best #2, table Default-IP-Routing-Table)
Flag: 0x208
  Not advertised to any peer
  23549
    64.152.195.33 (inaccessible) from 217.212.242.2 (217.212.243.253)
      Origin IGP, metric 0, localpref 100, valid, internal
  1299 3356 11908 10530 23549
    213.248.97.89 from 213.248.97.89 (80.239.146.12)
      Origin IGP, localpref 100, valid, external, best

Any reason as to why it keeps flapping? The router  217.212.242.2 
(217.212.243.253) that's sending the update does not seem to have a problem.

-- 
Richard