[c-nsp] BGP prepend problems

[Scott Granados]

Could be any number of things but most likely local pref.


Remember that some other metrics take priority so for example, if that
carrier is adjusting the pref of the routes that it learns which
includes yours, prepends won't make a difference as I understand it.
Local pref is considered before prepends.



-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Alain Cocconi
Sent: Tuesday, July 25, 2006 5:12 PM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] BGP prepend problems

Hello,

I'm advertising routes with prepends but some backbone's routers doesn't

care about my prepends
Does anybody has an idea about what's happenning ?

tia

Here is a sample :

--- Due to prepends, it should not be in routing tables ...---

# route-views.ab.bb.telus.com   --   TELUS Alberta BGP Route Viewer

route-views.ab>sh ip bgp 203.147.68.0
BGP routing table entry for 203.147.64.0/20, version 25483420
Bestpath Modifiers: deterministic-med
Paths: (1 available, best #1)
 Not advertised to any peer
 852 7473 7474 18117 18200 17480 17480 17480 17480 17480 17480
   154.11.98.17 from 154.11.98.17 (154.11.0.71)
     Origin IGP, localpref 100, valid, external, best


--- This one is ok ---

#BROADNET AG - Route-views Server

route-views>sh ip bgp 203.147.68.0
BGP routing table entry for 203.147.64.0/20, version 118838719
Paths: (1 available, best #1, table Default-IP-Routing-Table)
Multipath: eBGP iBGP
 Advertised to peer-groups:
    routeview
 4565 13589 17480, (received & used)
   206.223.115.52 (metric 60) from 194.140.115.2 (194.140.115.2)
     Origin incomplete, metric 202, localpref 110, valid, internal, best
     Community: 9132:3 9132:502 9132:666 9132:667 9132:2030 9132:2538
     Originator: 1


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