[c-nsp] show mBGP vpn advertized routes

Peter Rathlev peter at rathlev.dk
Wed Feb 25 14:25:01 EST 2009


On Wed, 2009-02-25 at 10:45 -0800, Marlon Duksa wrote:
> ok. Thanks.But the next hop is still not right. It shows  this below in red

In red? On my monochrome display? ;-)

> when my advertised next hop is 1.1.1.1. I checked that by capturing BGP
> Update message.
> Does anyone know why would next hop be displayed as 0.0.0.0.

When you see "0.0.0.0" as next hop in the BGP table it means that the
prefix is originated on this router itself. Consult the RIP ("show ip
route vrf ipvpn_1 191.1.0.0") or FIB ("show ip cef vrf ipvpn_1
191.1.0.0") to find out exactly what routing decision the box makes.

> 7609s#show   bgp vpnv4 unicast vrf ipvpn_1 191.1.0.0/24
> BGP routing table entry for 1:0:191.1.0.0/24, version 3
> Paths: (1 available, best #1, table ipvpn_1)
>   Advertised to update-groups:
>      2          1
>   Local
>     0.0.0.0 from 0.0.0.0 (191.1.0.1)
>       Origin incomplete, metric 0, localpref 100, weight 32768, valid,
> sourced, best
>       Extended Community: RT:1:0
>       mpls labels in/out IPv4 VRF Aggr:20/nolabel(ipvpn_1)

So this prefix is from yourself ("7609s"). The prefix has been
redistributed maybe with "redistribute connected" in the configuration.
You announce an aggregate label for the whole VRF, which covers all
connected prefixes. (Aggregate labels will make you PFC do a FIB lookup
to find out where to send the packets.)

Regards,
Peter




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