SR and LDP Interworking - End To End Packet Flow of VPNv4

This post is in continuation of previous post of SR and LDP Interworking which explains how green field deployment of segment routing inter works with brownfield deployment of LDP. In this post I will be covering how VPNv4 will work in the same topology.

       
Do we really need SRMS functionality? Stay tuned for upcoming posts.

We have already setup the SR control plane in the previous post. Let's see how vpnv4 control plane will setup in case of inter working.

RR-8 is route reflector for SR and LDP domain. L3,L4 and PE7 has MP-iBGP established with RR-8.

L4 BGP Neighborship with RR-8

       

RP/0/0/CPU0:L4#show bgp vpnv4 unicast summary
BGP router identifier 4.4.4.4, local AS number 100
Neighbor        Spk    AS MsgRcvd MsgSent   TblVer  InQ OutQ  Up/Down  St/PfxRcd
8.8.8.8           0   100      71      68       18    0    0 00:43:00          2

Output of vrf test on L4

       

RP/0/0/CPU0:L4#show route vrf test
B    100.0.0.3/32 [200/0] via 3.3.3.3 (nexthop in vrf default), 00:43:19
L    100.0.0.4/32 is directly connected, 01:16:50, Loopback100
B    100.0.0.7/32 [200/0] via 7.7.7.7 (nexthop in vrf default), 00:43:19
RP/0/0/CPU0:L4#

Check the below output where 100.0.0.4/32 is advertised with local label 24000

       

RP/0/0/CPU0:L4#show bgp vpnv4 unicast vrf test 100.0.0.4/32
Thu Apr 23 07:22:22.670 UTC
BGP routing table entry for 100.0.0.4/32, Route Distinguisher: 100:100
Versions:
  Process           bRIB/RIB  SendTblVer
  Speaker                  5           5
    Local Label: 24000
Last Modified: Apr 23 06:02:51.935 for 01:19:30
Paths: (1 available, best #1)
  Advertised to peers (in unique update groups):
    8.8.8.8
  Path #1: Received by speaker 0
  Advertised to peers (in unique update groups):
    8.8.8.8
  Local
    0.0.0.0 from 0.0.0.0 (4.4.4.4)
      Origin incomplete, metric 0, localpref 100, weight 32768, valid, redistributed, best, group-best, import-candidate
      Received Path ID 0, Local Path ID 1, version 5
      Extended community: RT:100:100
RP/0/0/CPU0:L4#

Check the below output where 100.0.0.4/32 is received by PE7(LDP Domain) with received label 24000

       

RP/0/0/CPU0:PE7#show bgp vpnv4 unicast vrf test 100.0.0.4/32
Thu Apr 23 07:20:17.429 UTC
BGP routing table entry for 100.0.0.4/32, Route Distinguisher: 100:100
Versions:
  Process           bRIB/RIB  SendTblVer
  Speaker                 15          15
Last Modified: Apr 23 06:34:21.928 for 00:45:55
Paths: (1 available, best #1)
  Not advertised to any peer
  Path #1: Received by speaker 0
  Not advertised to any peer
  Local
    4.4.4.4 (metric 40) from 8.8.8.8 (4.4.4.4)
      Received Label 24000
      Origin incomplete, metric 0, localpref 100, valid, internal, best, group-best, import-candidate, imported
      Received Path ID 0, Local Path ID 1, version 15
      Extended community: RT:100:100
      Originator: 4.4.4.4, Cluster list: 8.8.8.8
      Source AFI: VPNv4 Unicast, Source VRF: test, Source Route Distinguisher: 100:100

Output of end to end vrf traceroute on PE7

       

RP/0/0/CPU0:PE7#traceroute vrf test 100.0.0.4
 1  6.7.0.6 [MPLS: Labels 24020/24000 Exp 0] 29 msec  29 msec  29 msec
 2  5.6.0.5 [MPLS: Labels 24019/24000 Exp 0] 19 msec  19 msec  19 msec
 3  2.5.0.2 [MPLS: Labels 16004/24000 Exp 0] 39 msec  19 msec  29 msec
 4  2.4.0.4 19 msec  *  19 msec

End To End Packet Flow

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