bgp output interpretation

Unanswered Question
Apr 13th, 2009

Hi,

What does the below output means.This is from a bgp running router.

s ip bgp vpnv4 vrf V23456:abcd

BGP table version is 145693421, local router ID is 221.45.67.31

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

Route Distinguisher: 65000:23456 (default for vrf V23456:abcd)

*>i0.0.0.0 159.24.197.147 0 100 0 1 i

*> 100.26.0.0/18 87.32.21.8 0 0 1 ?

*> 100.33.1.0/28 87.32.21.8 0 0 1 ?

* i100.84.0.0/18 63.51.27.2 0 100 0 6500 ?

*>i 59.14.76.194 0 100 0 6500 ?

* i100.70.1.0/28 63.51.27.2 0 100 0 6500 ?

*>i 59.14.76.194 0 100 0 6500 ?

Thanks.

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lamav Mon, 04/13/2009 - 05:11

Hi:

There is a whole heck of a lot to say about this output. What exactly do you want to understand?

It is showing some bgp table information for a specific VRF instance on that router.

Victor

Giuseppe Larosa Mon, 04/13/2009 - 11:12

Hello Sunny,

as Victor says a lot of things could be said.

First of all, there is a default route coming from next hop 159.24.197.147 with metric 0, local pref 100, weight 0, with AS path = "1" and origin code internal (i).

This probably provides the exit point to internet.

In the same way you can go on and analyze the other prefixes:

100.26.0.0/18 with next-hop 87.32.21.8 from AS 1 (origin ? redistributed into BGP)

Then there are 2 prefixes learned by an iBGP session (the i on the left second position means iBGP)

for prefix 100.84.0.0/18 the best path is that via 59.14.76.194 (> means best)

Another path exists via 63.51.27.2.

Actually the same happens for prefix 100.70.1.0/28.

iBGP neighbor 59.14.76.194 can have a better lower IGP metric or simply it has a lower BGP router-id (that can be the same ip address or another one).

Hope to help

Giuseppe

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