[c-nsp] BGP best path

Mikisa Richard rmikisa at bushnet.net
Tue May 2 10:30:21 EDT 2006


Oliver Boehmer (oboehmer) wrote:

>Could this be a routing recursion? BGP next-hop 64.152.195.33 learnt via
>BGP? What is the 64.152.195.33 address? Can you use next-hop-self on the
>neighbor peering with AS23549?
>
>	oli
>
>  
>
telia(AS1299)----BUSH-UPLINK(AS29032)---UPLINK(29032)----Customer(AS23549)
213.248.97.89    217.212.242.1         217.212.242.2	  64.152.152.195 


That's the lay out. The session between 217.212.242.2 and the customer
(64.152.195.33) seems ok ..

UPLINK#show ip bgp nei 64.152.195.33 ro
BGP table version is 309, local router ID is 217.212.243.253
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
*> 63.103.129.0/24  64.152.195.33            0             0 23549 i
*> 64.152.195.0/24  64.152.195.33            0             0 23549 i

Total number of prefixes 2

Then the UPLINK ( 217.212.242.2) does iBGP with 217.212.242.1...

UPLINK#show ip bgp neighbors 217.212.243.254 ad
BGP table version is 316, local router ID is 217.212.243.253
   Network          Next Hop            Metric LocPrf Weight Path
*> 41.220.0.0/20    0.0.0.0                  0         32768 i
*> 41.220.1.0/26    217.212.242.23           0         32768 ?
*> 41.220.13.0/24   217.212.242.14           0         32768 ?
*> 41.220.14.0/23   217.212.242.13           0         32768 ?
*> 63.103.129.0/24  64.152.195.33            0             0 23549 i
*> 64.152.195.0/24  64.152.195.33            0             0 23549 i
*> 64.152.195.33/32 0.0.0.0                  0         32768 ?

and ....

BUSH-UPLINK-01#show ip bgp ne 217.212.242.2 ro
BGP table version is 558467, local router ID is 217.212.243.254
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
* i41.220.0.0/20    217.212.242.2            0    100      0 i
*>i41.220.13.0/24   217.212.242.14           0    100      0 ?
*>i41.220.14.0/23   217.212.242.13           0    100      0 ?
* i63.103.129.0/24  64.152.195.33            0    100      0 23549 i
* i64.152.195.0/24  64.152.195.33            0    100      0 23549 i

Total number of prefixes 5

Hopefully that makes more sense.

-- 
Richard




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