Saku Ytti wrote:
On (2009-02-28 18:05 +0100), sthaug@nethelp.no wrote:
show route 195.128.231.0/24 detail [..omitted..] AS path: AS2 PA[5]: 39792 35320 AS_TRANS AS_TRANS 35748 AS path: AS4 PA[4]: 35320 3.21 AS_TRANS 35748 AS path: Merged[5]: 39792 35320 3.21 AS_TRANS 35748 I [...omitted...] Agreed, that sounds wrong. However, that's not how the route appears from here:
show route 195.128.231.0/24 detail | match "AS path: [0-9AM]" AS path: AS2 PA[5]: 3356 13249 6886 AS_TRANS 35748 AS path: AS4 PA[4]: 13249 6886 196629 35748 AS path: Merged[5]: 3356 13249 6886 196629 35748 I AS path: AS2 PA[6]: 1299 3356 13249 6886 AS_TRANS 35748 AS path: AS4 PA[4]: 13249 6886 196629 35748 AS path: Merged[6]: 1299 3356 13249 6886 196629 35748 I
So in our case the AS4 path seems normal.
Looks OK in cisco as-dot format too, so unlike first example, I think this may be local problem.
gw.ip.fi#show ip bgp 195.128.231.0/24 BGP routing table entry for 195.128.231.0/24, version 29 Paths: (1 available, best #1, table Default-IP-Routing-Table) Multipath: eBGP Not advertised to any peer 3292 3356 13249 6886 3.21 35748, (received & used) 62.237.167.25 from 62.237.167.25 (62.236.0.5) Origin IGP, localpref 100, valid, external, best Community: 3292:1101 3292:1901 gw.ip.fi#
We have same result, like the first example from Steinar Haug.
show route 195.128.231.0/24 detail | match "AS path" AS path: AS2 PA[6]: 15685 29208 35320 AS_TRANS AS_TRANS 35748 AS path: AS4 PA[4]: 35320 196629 AS_TRANS 35748 AS path: Merged[6]: 15685 29208 35320 196629 AS_TRANS 35748 I ... AS path: AS2 PA[7]: 9002 13249 13249 13249 6886 AS_TRANS 35748 AS path: AS4 PA[6]: 13249 13249 13249 6886 196629 35748 AS path: Merged[7]: 9002 13249 13249 13249 6886 196629 35748 I
Note: If propagated via AS196629,AS35320,.... then the AS4_PATH contains AS_TRANS. Em.