MPLS INTER-AS L3 VPN OPTION B

Hi All,

This question is regarding the CCIE SP ATC V4 video MPLS L3VPN Inter-AS Option B  Part 1 and MPLS L3VPN Inter-AS Option B  Part 2.

Topology is same as CCIE SP V4 ATC

 

Problem description

============

 

R3 is not generating the vpnv4 label for the prefixes received from XR3, If next-hop-self is not confiured towards R1.

 

R3

==

 

interface GigabitEthernet1/0.313

 encapsulation dot1Q 313

 ip address 10.3.13.3 255.255.255.0

 mpls bgp forwarding

end

 

R3 ospf and BGP config

==============

router ospf 1

 redistribute connected subnets

 mpls ldp autoconfig

 

router bgp 123

 bgp asnotation dot

 bgp log-neighbor-changes

 no bgp default ipv4-unicast

 no bgp default route-target filter

 neighbor 1.1.1.1 remote-as 123

 neighbor 1.1.1.1 update-source Loopback0

 neighbor 10.3.13.13 remote-as 11.1213

 !

 address-family ipv4

 exit-address-family

 !

 address-family vpnv4

  neighbor 1.1.1.1 activate

  neighbor 1.1.1.1 send-community extended

  neighbor 10.3.13.13 activate

  neighbor 10.3.13.13 send-community extended

 exit-address-family

 

 10.3.13.13/32 is advertising via OSPF as external route

 ====================================

 

sh ip ospf database external 10.3.13.13

 

            OSPF Router with ID (3.3.3.3) (Process ID 1)

 

                Type-5 AS External Link States

 

  LS age: 195

  Options: (No TOS-capability, DC, Upward)

  LS Type: AS External Link

  Link State ID: 10.3.13.13 (External Network Number )

  Advertising Router: 3.3.3.3

  LS Seq Number: 80000001

  Checksum: 0xD498

  Length: 36

  Network Mask: /32

        Metric Type: 2 (Larger than any link state path)

        MTID: 0 

        Metric: 20 

        Forward Address: 0.0.0.0

        External Route Tag: 0

 

 

 

 

R3 is not allocating labeles for the prefixes learning from XR3

=======================================

sh bgp vpnv4 unicast all 8.8.8.8/32

BGP routing table entry for 200:200:8.8.8.8/32, version 6

Paths: (1 available, best #1, no table)

  Advertised to update-groups:

     10        

  Refresh Epoch 1

  11.1213

    10.3.13.13 from 10.3.13.13 (13.13.13.13)

      Origin incomplete, localpref 100, valid, external, best

      Extended Community: RT:200:200 0x8800:32768:0 0x8801:200:128256 

        0x8802:65281:2560 0x8803:1:1500 0x8806:0:134744072

      mpls labels in/out nolabel/24013

      rx pathid: 0, tx pathid: 0x0

 

R3#sh mpls forwarding-table  

Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    

Label      Label      or Tunnel Id     Switched      interface              

16         Pop Label  2.2.2.2/32       0             Gi1/0.23   10.2.3.2    

17         16         1.1.1.1/32       0             Gi1/0.23   10.2.3.2    

18         Pop Label  10.1.2.0/24      0             Gi1/0.23   10.2.3.2    

19         19         200:200:10.10.10.10/32  

                                       49166         Gi1/0.23   10.2.3.2    

20         18         200:200:10.2.10.0/24  

                                       0             Gi1/0.23   10.2.3.2    

30         Pop Label  10.3.13.13/32    0             Gi1/0.313  10.3.13.13  

 

 

After configuring next-hop-self to R1 (RR),  R3 starts allocating labels for the routes coming from XR3

==================================================================

 

R3(config)#router bgp 123

R3(config-router)#address-family vpnv4

R3(config-router-af)#  neighbor 1.1.1.1 next-hop-self 

R3(config-router-af)#end

 

 

R3#sh bgp vpnv4 unicast all 8.8.8.8/32    

BGP routing table entry for 200:200:8.8.8.8/32, version 6

Paths: (1 available, best #1, no table)

  Advertised to update-groups:

     12        

  Refresh Epoch 1

  11.1213

    10.3.13.13 from 10.3.13.13 (13.13.13.13)

      Origin incomplete, localpref 100, valid, external, best

      Extended Community: RT:200:200 0x8800:32768:0 0x8801:200:128256 

        0x8802:65281:2560 0x8803:1:1500 0x8806:0:134744072

      mpls labels in/out 31/24013

 

 

R3#sh mpls forwarding-table 

Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    

Label      Label      or Tunnel Id     Switched      interface              

16         Pop Label  2.2.2.2/32       0             Gi1/0.23   10.2.3.2    

17         16         1.1.1.1/32       0             Gi1/0.23   10.2.3.2    

18         Pop Label  10.1.2.0/24      0             Gi1/0.23   10.2.3.2    

19         19         200:200:10.10.10.10/32  

                                       49166         Gi1/0.23   10.2.3.2    

20         18         200:200:10.2.10.0/24  

                                       0             Gi1/0.23   10.2.3.2    

21         24011      100:100:10.4.6.0/24  

                                       0             Gi1/0.313  10.3.13.13  

22         24009      100:100:4.4.4.4/32  

                                       0             Gi1/0.313  10.3.13.13  

26         24014      200:200:10.8.9.0/24  

                                       0             Gi1/0.313  10.3.13.13  

27         24010      100:100:10.4.5.0/24  

                                       0             Gi1/0.313  10.3.13.13  

28         24015      200:200:10.8.11.0/24  

                                       0             Gi1/0.313  10.3.13.13  

29         24012      100:100:10.4.11.0/24  

                                       0             Gi1/0.313  10.3.13.13  

30         Pop Label  10.3.13.13/32    0             Gi1/0.313  10.3.13.13  

Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    

Label      Label      or Tunnel Id     Switched      interface              

31         24013      200:200:8.8.8.8/32  

                                       0             Gi1/0.313  10.3.13.13    

 

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