[j-nsp] RFC3107 to LDP stitching

[Krasimir Avramski]

Hi Adam,


And cmd: “set protocols bgp group nni-opt-c family inet labeled-unicast
> per-prefix-label”
> -only creates label mapping for BGP-LU label that remote AS ASBR
> advertised for remote AS PE loopback with LDP label that local AS ASBR
> allocated for this prefix.
>

I don't think per-prefix-label has anything to do with stitching. IMHO
stitching in that direction is done through bgp --> ldp redistribution
policy ( usually "ldp egress-policy ....") or bgp-lu is extended from ASBRs
to the local PEs as typical inter-as option C
<http://www.juniper.net/techpubs/en_US/junose12.3/topics/concept/mbgp-inter-as-option-c-overview.html#id-35896>
scenario.

So now the only mystery is the need for explicit null label advertised by
> local AS ASBR (acting as PE) for its own loopback to remote AS ASBR
> Without this the VPN ping doesn’t work
> But it might something to do with the vrf table-label
>

This works for me without explicit-null and in disregard of vrf-table-label.

I recommend to reconsider mp-bgp with AFI=1, SAFI=1,4 as more flexible way
than bgp-igp-both-ribs/resolve-vpn. Note that you still need to
redistribute ldp from inet.3 and isis from inet.0 through bgp policy on
both ASBRs. The tricky part here is to leak ASBRs loopback routes also in
inet.3 - (i.e.  interface-routes rib-group controlled through
"import-policy")

In summary if you don't want to extend bgp-lu to all PEs then you need
mutual redistribution between ldp/isis and bgp-lu in order to stitch lsp
transport.

Best Regards,
Krasi