LDP binding

Experts,
I was under the impression that LDP associates a label to ONLY locally
attached or IGP prefixes in the routing table, and never to BGP
prefixes. But look at this:

R2#show ip route vrf C1 1.0.0.5 255.255.255.255
Routing entry for 1.0.0.5/32
  Known via "bgp 24", distance 200, metric 65, type internal
  Redistributing via ospf 24
  Advertised by ospf 24 subnets
  Last update from 1.0.0.4 01:03:22 ago
  Routing Descriptor Blocks:
  * 1.0.0.4 (Default-IP-Routing-Table), from 1.0.0.4, 01:03:22 ago
      Route metric is 65, traffic share count is 1
      AS Hops 0

R2#show mpls ldp bindings vrf C1 1.0.0.5 32 detail
  tib entry: 1.0.0.5/32, rev 16
        local binding: tag: 24
          Advertised to:
          1.0.0.1:0
        remote binding: tsr: 1.0.0.1:0, tag: 20

The scenario is the following:
R2 is a CarrierSupportingCarrier PE router learning 1.0.0.5/32 via MBGP
and redistributing it in OSPF 24 which is the CSC_PE <-> CustomerCarrier
protocol: 1.0.0.5 is one of the CustomerCarrier's internal loopback.
R2 runs LDP towards its CustomerCarrier to create the end-to-end LSP.
1.0.0.5 is in the routing-table of R2 in the correct vrf C1 as BGP
route.
Why then LDP creates a binding for it if it is not an IGP route?

I understand that it would have not working otherwise, and indeed it
works as it is :-), but this was not supposed to be LDP job....

Thanks,
bit.

PS: someone can point me towards an example of CsC where BGP+label is
used between CsC and CustomerCarrier?

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Received on Sun May 09 2010 - 10:15:42 ART