BGP+Label issue

Hi All,

I'm practising on the Cisco CCIE Sample lab for service provider.
https://learningnetwork.cisco.com/servlet/JiveServlet/download/149550-38956/CCIE%20SP%20v3.0%20Sample%20Lab%20Part%20-%204%20of%207.pdf

I encountered on a issue with the CSC configuration specifically with BGP
plus label between R3 (IOS) and R8 (XR). I have configured LDP between R7
and R1. R8 and R7 are two of the backbone routers and serve as PE to R1 and
R3.

With BGP+Label configured between R3 and R8 I cannot get up communication
between R1 and R3 loopback interfaces. As soon as I remove the BGP+label
config reachablility is restored. When I debug with BGP+Label activated I
can see R3 is able to reach out to R1 but when R1 sends packets back to R3
it gets dropped on R8. R7 has VPN label 16008 in it MPLS forwarding table
this is also listed as local label on R8. But R8 drops the packet because
it has no LFIB entry.

R1 loopback 172.2.0.1
R3 loopback 172.2.0.3

See below the MPLS forwarding table of R7
R7#sh mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
16 No Label 172.2.0.1/32[V] 30269 Et0/0.17 172.2.17.1
17 Pop Label 2.2.0.2 279 [4] 0 Et0/0.79 2.2.79.9
19 Pop Label 2.2.0.2/32 0 Et0/0.27 2.2.27.2
20 Pop Label 2.2.0.8/32 15100 Et0/0.78 2.2.78.8
21 Pop Label 2.2.0.9/32 645 Et0/0.79 2.2.79.9
22 Pop Label 2.2.28.0/24 0 Et0/0.27 2.2.27.2
           Pop Label 2.2.28.0/24 0 Et0/0.78 2.2.78.8
23 Pop Label 2.2.29.0/24 0 Et0/0.27 2.2.27.2
           Pop Label 2.2.29.0/24 0 Et0/0.79 2.2.79.9
24 24 2.2.0.8 89 [9] 484480 Et0/0.27 2.2.27.2
26 Pop Label 172.2.17.0/24[V] 0 aggregate/ABC
27 16008 172.2.0.3/32[V] 11520 Et0/0.78 2.2.78.8
28 16011 172.2.0.5/32[V] 0 Et0/0.79 2.2.79.9
29 16014 172.2.0.12/32[V] 732 Et0/0.79 2.2.79.9
30 17 172.2.0.14/32[V] 0 Et0/0.27 2.2.27.2
31 16009 172.2.38.0/24[V] 0 Et0/0.78 2.2.78.8
32 16017 172.2.38.8/32[V] 0 Et0/0.78 2.2.78.8
33 16007 172.2.59.0/24[V] 0 Et0/0.79 2.2.79.9
34 16018 172.2.126.0/24[V] \
                                       0 Et0/0.79 2.2.79.9
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
35 16 172.2.142.0/24[V] \
                                       0 Et0/0.27 2.2.27.2

See below the MPLS forwarding table of R8
RP/0/0/CPU0:R8#sh mpls forwarding
Mon Jul 14 00:58:38.436 UTC
Local Outgoing Prefix Outgoing Next Hop
Bytes
Label Label or ID Interface
Switched
------ ----------- ------------------ ------------ ---------------
------------
16000 Pop 2.2.0.7/32 Gi0/0/0/0.78 2.2.78.7
39344
16001 Pop 2.2.79.0/24 Gi0/0/0/0.78 2.2.78.7
0
16002 Pop 2.2.27.0/24 Gi0/0/0/0.28 2.2.28.2
0
       Pop 2.2.27.0/24 Gi0/0/0/0.78 2.2.78.7
0
16003 Pop 2.2.0.9/32 tt89 2.2.0.9
0
16004 Pop 2.2.0.2/32 Gi0/0/0/0.28 2.2.28.2
15126
16005 Pop 2.2.29.0/24 Gi0/0/0/0.28 2.2.28.2
0
16007 16 172.2.0.1/32[V] 2.2.0.7
12053
16008 Pop 172.2.0.3/32[V] 172.2.38.3
0
16009 Aggregate 172.2.38.0/24[V] ABC
0
16010 16011 172.2.0.5/32[V] 2.2.0.9
0
16011 16014 172.2.0.12/32[V] 2.2.0.9
0
16012 17 172.2.0.14/32[V] 2.2.0.2
0
16013 26 172.2.17.0/24[V] 2.2.0.7
0
16014 16007 172.2.59.0/24[V] 2.2.0.9
0
16015 16018 172.2.126.0/24[V] 2.2.0.9
0
16016 16 172.2.142.0/24[V] 2.2.0.2
0
16017 Unlabelled 172.2.38.8/32[V] point2point
0

Debug out on R8
RP/0/0/CPU0:Jul 14 00:45:34.700 : netio[309]: mpls_get_payload_start: ipv4:
src=172.2.0.1, dst=172.2.0.3
RP/0/0/CPU0:Jul 14 00:45:34.700 : netio[309]: mpls_get_payload_start: src.
port = 0x56bb, dst. port = 0xb3, protocol = 0x6
RP/0/0/CPU0:Jul 14 00:45:34.700 : netio[309]: mpls_switch:
GigabitEthernet0_0_0_0.78, mpls eos 1, ttl 254, len 66, inlabel 16008,
tbl_id=0xe0000007, vrf_id=0x60000007 in=0x1300
RP/0/0/CPU0:Jul 14 00:45:34.700 : netio[309]: [mpls_switch:2773] Pkt Drop:
mpls_switch: GigabitEthernet0_0_0_0.78, No LFIB entry found for in_label
16008

Config R8
RP/0/0/CPU0:R8#sh runn router bgp
Mon Jul 14 01:00:07.940 UTC
router bgp 2
 address-family ipv4 unicast
 !
 address-family vpnv4 unicast
 !
 neighbor 2.2.0.9
  remote-as 2
  update-source Loopback0
  address-family vpnv4 unicast
  !
 !
 vrf ABC
  rd 2:2
  address-family ipv4 unicast
   allocate-label all
  !
  neighbor 172.2.38.3
   remote-as 123
   address-family ipv4 unicast
    send-community-ebgp
    route-policy PERMIT_ALL in
    route-policy PERMIT_ALL out
    send-extended-community-ebgp
   !
   address-family ipv4 labeled-unicast
    route-policy PERMIT_ALL in
    route-policy PERMIT_ALL out
    as-override
    send-extended-community-ebgp
   !
  !
 !
!
RP/0/0/CPU0:R8#sh runn mpls
Mon Jul 14 01:00:13.759 UTC
mpls traffic-eng
 interface GigabitEthernet0/0/0/0.28
 !
 interface GigabitEthernet0/0/0/0.78
 !
!
mpls ldp
 router-id 2.2.0.8
 interface GigabitEthernet0/0/0/0.28
 !
 interface GigabitEthernet0/0/0/0.78
 !
!
RP/0/0/CPU0:R8#

Thanks in advance for helping me understand this better

Maarten

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Received on Mon Aug 04 2014 - 22:15:25 ART