Re: mpls vpn's

Via the CEF/LFIB.

Joe Sanchez
Sent from my iPad

On May 15, 2013, at 5:48 AM, Paul Cocker <groupstudy_at_paulcocker.net> wrote:

> Hi Group, hope you don't get duplicates of this mail. I've just switched to
> another email as nothing was getting though.
>
> Wonder if someone can clear up a query for me. I'm working through Narbiks
> MPLS section in his R&S workbook. I'm on the start of the MPLS VPN section.
>
> R1 ----- R3 ------ R2 ------- R4 ------ R5
>
> r1/r5 are CE's
> r3 / r4 are PE's
> R2 is a P
>
> On one PE , we have the following route for the other end of the network on
> R1.
>
> R4#sh ip bgp vpnv4 vrf CB 1.0.0.0
> BGP routing table entry for 1:20:1.0.0.0/8, version 8
> Paths: (1 available, best #1, table CB)
> Not advertised to any peer
> Local, imported path from 1:10:1.0.0.0/8
> 3.3.3.3 (metric 3) from 3.3.3.3 (3.3.3.3)
> Origin incomplete, metric 1, localpref 100, valid, internal, best
> Extended Community: RT:1:100
> mpls labels in/out nolabel/303
>
> So it uses label 303 for this. But how does it know which interface to
> use? I can't find 303 in the following tables,
>
> sh mpls forwarding table
> sh mpls ldp bindings
> sh mpls ip binding
>
> nor can I find it mentioned in the tables on the P router.
>
> I'm obviously missing something, as it works just fine end to end! Can
> someone explain how this works in LDP all the way to R1?
>
> Paul
>
>
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Received on Wed May 15 2013 - 06:44:16 ART