Re: BGP+Label issue

Hi Group,

It helps when you write things down. I solved th issue. I needed to add a
static /32 route for the next-hop for it to allocate a label

router static
 vrf ABC
  address-family ipv4 unicast
   172.2.38.3/32 GigabitEthernet0/0/0/0.38
  !

Maarten

2014-08-04 22:15 GMT+02:00 Maarten Vervoorn <mr.vervoorn_at_gmail.com>:

> 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] <http://172.2.0.1/32%5BV%5D>
> 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] <http://172.2.17.0/24%5BV%5D>
> 0 aggregate/ABC
> 27 16008 172.2.0.3/32[V] <http://172.2.0.3/32%5BV%5D>
> 11520 Et0/0.78 2.2.78.8
> 28 16011 172.2.0.5/32[V] <http://172.2.0.5/32%5BV%5D>
> 0 Et0/0.79 2.2.79.9
> 29 16014 172.2.0.12/32[V] <http://172.2.0.12/32%5BV%5D>
> 732 Et0/0.79 2.2.79.9
> 30 17 172.2.0.14/32[V] <http://172.2.0.14/32%5BV%5D>
> 0 Et0/0.27 2.2.27.2
> 31 16009 172.2.38.0/24[V] <http://172.2.38.0/24%5BV%5D>
> 0 Et0/0.78 2.2.78.8
> 32 16017 172.2.38.8/32[V] <http://172.2.38.8/32%5BV%5D>
> 0 Et0/0.78 2.2.78.8
> 33 16007 172.2.59.0/24[V] <http://172.2.59.0/24%5BV%5D>
> 0 Et0/0.79 2.2.79.9
> 34 16018 172.2.126.0/24[V] <http://172.2.126.0/24%5BV%5D> \
> 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] <http://172.2.142.0/24%5BV%5D> \
> 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] <http://172.2.0.1/32%5BV%5D>
> 2.2.0.7 12053
> 16008 Pop 172.2.0.3/32[V] <http://172.2.0.3/32%5BV%5D>
> 172.2.38.3 0
> 16009 Aggregate 172.2.38.0/24[V] <http://172.2.38.0/24%5BV%5D>
> ABC 0
> 16010 16011 172.2.0.5/32[V] <http://172.2.0.5/32%5BV%5D>
> 2.2.0.9 0
> 16011 16014 172.2.0.12/32[V] <http://172.2.0.12/32%5BV%5D>
> 2.2.0.9 0
> 16012 17 172.2.0.14/32[V] <http://172.2.0.14/32%5BV%5D>
> 2.2.0.2 0
> 16013 26 172.2.17.0/24[V] <http://172.2.17.0/24%5BV%5D>
> 2.2.0.7 0
> 16014 16007 172.2.59.0/24[V] <http://172.2.59.0/24%5BV%5D>
> 2.2.0.9 0
> 16015 16018 172.2.126.0/24[V] <http://172.2.126.0/24%5BV%5D>
> 2.2.0.9 0
> 16016 16 172.2.142.0/24[V] <http://172.2.142.0/24%5BV%5D>
> 2.2.0.2 0
> 16017 Unlabelled 172.2.38.8/32[V] <http://172.2.38.8/32%5BV%5D>
> 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 - 22:26:17 ART