7 Replies Latest reply: Jun 2, 2019 10:05 AM by nammon RSS

    IPv6 bgp neighbor

    nammon

      Hi all,

      I have a topology:

      I want to form iBGP IPv6 Unicast neighbor between R2 (regular IOS) and XR1 (IOS XR) via their IPv4 loopback.

      R2

      router bgp 100

      neighbor 19.19.19.19 remote-as 100

      neighbor 19.19.19.19 update-source Loopback0

      !

      address-family ipv6

        neighbor 19.19.19.19 activate

        neighbor 19.19.19.19 send-label

      exit-address-family

      !

       

      XR1

      router bgp 100

      address-family ipv6 unicast

        allocate-label all

      !

      neighbor 2.2.2.2

        remote-as 100

        update-source Loopback0

        address-family ipv6 labeled-unicast

        !

      !

      !

       

      I see that R2 can form iBGP IPv6 Unicast neighbor with XR1, but XR1 can't.

      In XR1, I see a log "detected missing neighbor af sub-group ..."

      Hope your help.

      Thank in advance!

        • 1. Re: IPv6 bgp neighbor
          Juergen Ilse CCNA R&S

          nammon schrieb:


          I have a topology:

          I want to form iBGP IPv6 Unicast neighbor between R2 (regular IOS) and XR1 (IOS XR) via their IPv4 loopback.

          I think, you can do ipv6 bgp peering via ipv4 addresses only, if you override the next hop with the according ipv6 gateway address, which is usually done with a route-map. I didn't saw such configuration in your configs ...

          Or if you use MPLSbetween the peers. Do you have an MPLS connection between your peer ipv4 ip  addresses?

          • 2. Re: IPv6 bgp neighbor
            nammon

            In this lab, I want to build IPv4 and IPv6 BGP neighbor relationship between R2 and XR1 so that thay can exchange IPv4 and IPv6 prefixes learned from R1 and XR2.

            This is all my configuration on R1, R2 and XR1, XR2:

            R1#show running-config | sec bgp

            router bgp 1

            bgp log-neighbor-changes

            no bgp default ipv4-unicast

            neighbor 10.1.2.2 remote-as 100

            neighbor 2001:10:1:2::2 remote-as 100

            !

            address-family ipv4

              network 1.1.1.1 mask 255.255.255.255

              neighbor 10.1.2.2 activate

            exit-address-family

            !

            address-family ipv6

              network 2001::1:1:1:1/128

              neighbor 2001:10:1:2::2 activate

            exit-address-family

             

            R2#show running-config | section bgp

            router bgp 100

            bgp log-neighbor-changes

            no bgp default ipv4-unicast

            neighbor 10.1.2.1 remote-as 1

            neighbor 19.19.19.19 remote-as 100

            neighbor 19.19.19.19 update-source Loopback0

            neighbor 2001:10:1:2::1 remote-as 1

            !

            address-family ipv4

              neighbor 10.1.2.1 activate

              neighbor 19.19.19.19 activate

              neighbor 19.19.19.19 next-hop-self

            exit-address-family

            !

            address-family ipv6

              neighbor 19.19.19.19 activate

              neighbor 19.19.19.19 send-label

              neighbor 2001:10:1:2::1 activate

            exit-address-family

             

            XR1

            router bgp 100

            address-family ipv4 unicast

            !

            address-family ipv6 unicast

            !

            neighbor 2.2.2.2

              remote-as 100

              update-source Loopback0

              address-family ipv4 unicast

               next-hop-self

              !

              address-family ipv6 labeled-unicast

              !

            !

            neighbor 10.19.20.20

              remote-as 20

              address-family ipv4 unicast

               route-policy PASS in

               route-policy PASS out

              !

            !

            neighbor 2001:10:19:20::20

              remote-as 20

              address-family ipv6 unicast

               route-policy PASS in

               route-policy PASS out

              !

            !

            !

             

            XR2

            router bgp 20

            address-family ipv4 unicast

              network 20.20.20.20/32

            !

            address-family ipv6 unicast

              network 2001::20:20:20:20/128

            !

            neighbor 10.19.20.19

              remote-as 100

              address-family ipv4 unicast

               route-policy PASS in

               route-policy PASS out

              !

            !

            neighbor 2001:10:19:20::19

              remote-as 100

              address-family ipv6 unicast

               route-policy PASS in

               route-policy PASS out

              !

            !

            !

            end

             

            R2 can form IPv4 and IPv6 neighbor relationship with XR1, it only can learn IPv4 prefixes (network 20.20.20.20/32) advertised from XR2.

            R2#show bgp ipv4 unicast summary

             

            Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd

            10.1.2.1        4            1      18      18        4    0    0 00:12:15        1

            19.19.19.19     4          100      21      25        4    0    0 00:16:20        1

            R2#show bgp ipv6 unicast summary

             

            Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd

            19.19.19.19     4          100      21      25        3    0    0 00:16:27        0

            2001:10:1:2::1  4            1      18      17        3    0    0 00:12:28        1

             

            R2#show bgp ipv4 unicast

            BGP table version is 4, local router ID is 2.2.2.2

            Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

                          r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

                          x best-external, a additional-path, c RIB-compressed,

            Origin codes: i - IGP, e - EGP, ? - incomplete

            RPKI validation codes: V valid, I invalid, N Not found

             

                 Network          Next Hop            Metric LocPrf Weight Path

            *>  1.1.1.1/32       10.1.2.1                 0             0 1 i

            *>i 20.20.20.20/32   19.19.19.19              0    100      0 20 i

            R2#show bgp ipv6 unicast

            BGP table version is 3, local router ID is 2.2.2.2

            Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

                          r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

                          x best-external, a additional-path, c RIB-compressed,

            Origin codes: i - IGP, e - EGP, ? - incomplete

            RPKI validation codes: V valid, I invalid, N Not found

             

                 Network          Next Hop            Metric LocPrf Weight Path

            *>  2001::1:1:1:1/128

                                   2001:10:1:2::1           0             0 1 i

             

            XR2 only form IPv4 neighbor relationship with XR1, didn't form IPv6 neighbor relationship (as result of show command ...), but it can learn both IPv4 and IPv6 prefixes advertised from R2:

            RP/0/0/CPU0:XR1#show bgp ipv4 unicast summary

             

            BGP is operating in STANDALONE mode.

             

             

            Process       RcvTblVer   bRIB/RIB   LabelVer  ImportVer  SendTblVer  StandbyVer

            Speaker               9          9          9          9           9           9

             

            Neighbor        Spk    AS MsgRcvd MsgSent   TblVer  InQ OutQ  Up/Down  St/PfxRcd

            2.2.2.2           0   100      28      24        9    0    0 00:19:21          1

            10.19.20.20       0    20      14      14        9    0    0 00:10:56          1

             

            RP/0/0/CPU0:XR1#show bgp ipv6 unicast summary

            BGP is operating in STANDALONE mode.

             

             

            Process       RcvTblVer   bRIB/RIB   LabelVer  ImportVer  SendTblVer  StandbyVer

            Speaker               7          7          7          7           7           7

             

            Neighbor        Spk    AS MsgRcvd MsgSent   TblVer  InQ OutQ  Up/Down  St/PfxRcd

            2001:10:19:20::20

                              0    20      14      15        7    0    0 00:10:57          1

             

            RP/0/0/CPU0:XR1#

            RP/0/0/CPU0:XR1#show bgp ipv4 unicast

               Network            Next Hop            Metric LocPrf Weight Path

            *>i1.1.1.1/32         2.2.2.2                  0    100      0 1 i

            *> 20.20.20.20/32     10.19.20.20              0             0 20 i

             

            Processed 2 prefixes, 2 paths

            RP/0/0/CPU0:XR1#show bgp ipv6 unicast

               Network            Next Hop            Metric LocPrf Weight Path

            *>i2001::1:1:1:1/128  2.2.2.2                  0    100      0 1 i

            *> 2001::20:20:20:20/128

                                  2001:10:19:20::20

                                                           0             0 20 i

             

            Processed 2 prefixes, 2 paths

             

             

            XR1 didn't advertised anything related to IPv6 prefixes to R2:

            RP/0/0/CPU0:XR1#show bgp ipv6 unicast neighbors 2.2.2.2 advertised-routes

            Sat May 25 14:49:56.350 UTC

            RP/0/0/CPU0:XR1#

             

            DO you have any idea about log "detected missing neighbor af sub-group ..."?

            • 3. Re: IPv6 bgp neighbor
              Martin

              is this based on INE SP lab?  what IOS XR version do u use? 

              • 4. Re: IPv6 bgp neighbor
                Martin

                Cisco Doc pages ahve errors listed, under following error :  Error Message %ROUTING-BGP-4-MISSING_SUBGRP

                 

                Detected missing neighbor AF sub-grp. Correcting: [chars]

                Explanation BGP detected that a Neighbor AF did not correctly belong to an update sub-group. BGP attempted to correct this error.

                Recommended Action Copy the error message exactly as it appears on the console or in the system log, call your Cisco technical support representative and provide the representative with the gathered information.

                 

                which probably means bug in IOS, see https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvf88842/?rfs=iqvred

                • 5. Re: IPv6 bgp neighbor
                  nammon

                  Yes Martin,

                  RP/0/0/CPU0:XR1#show version

                  Sun May 26 09:23:12.606 UTC

                   

                  Cisco IOS XR Software, Version 5.2.2[Default]

                  Copyright (c) 2014 by Cisco Systems, Inc.

                   

                  ROM: GRUB, Version 1.99(0), DEV RELEASE

                   

                  XR1 uptime is 8 minutes

                  System image file is "bootflash:disk0/xrvr-os-mbi-5.2.2/mbixrvr-rp.vm"

                   

                  cisco IOS XRv Series (Pentium Celeron Stepping 3) processor with 2096639K bytes                                                                                         of memory.

                  Pentium Celeron Stepping 3 processor at 2593MHz, Revision 2.174

                  IOS XRv Chassis

                  • 6. Re: IPv6 bgp neighbor
                    David

                    The feature you are trying to configure is called 6PE. You are trying to exchange labelled IPv6 routes over an IPv4 BGP session.

                     

                    I've labbed this up, and have it working with the same version of IOS-XR that you are running.

                     

                    My config is as follows:

                     

                    IOS-XE:

                    router bgp 100
                    bgp log-neighbor-changes
                    no bgp default ipv4-unicast
                    neighbor 10.1.1.3 remote-as 100
                    neighbor 10.1.1.3 update-source Loopback0
                    !
                    address-family ipv6
                      redistribute connected
                      neighbor 10.1.1.3 activate
                      neighbor 10.1.1.3 send-label
                    exit-address-family
                    

                     

                    IOS-XR:

                    router bgp 100
                    address-family ipv6 unicast
                      redistribute connected
                      allocate-label all
                    !
                    neighbor 10.1.1.1
                      remote-as 100
                      update-source Loopback0
                      address-family ipv6 labeled-unicast
                      next-hop-self
                      !
                    !
                    !
                    

                     

                    The routing tables look at each side:

                    R1(config-router-af)#do sho ipv6 route
                    IPv6 Routing Table - default - 3 entries
                    Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
                           B - BGP, R - RIP, H - NHRP, I1 - ISIS L1
                           I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary, D - EIGRP
                           EX - EIGRP external, ND - ND Default, NDp - ND Prefix, DCE - Destination
                           NDr - Redirect, RL - RPL, O - OSPF Intra, OI - OSPF Inter
                           OE1 - OSPF ext 1, OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1
                           ON2 - OSPF NSSA ext 2, la - LISP alt, lr - LISP site-registrations
                           ld - LISP dyn-eid, lA - LISP away, a - Application
                    LC  2001:DB8::1/128 [0/0]
                         via Loopback0, receive
                    B   2001:DB8::3/128 [200/0]
                         via 10.1.1.3%default, indirectly connected
                    L   FF00::/8 [0/0]
                         via Null0, receive
                    

                     

                    RP/0/0/CPU0:R3#sho route ipv6
                    Fri May 31 07:10:25.180 UTC
                    
                    
                    Codes: C - connected, S - static, R - RIP, B - BGP, (>) - Diversion path
                           D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
                           N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
                           E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
                           i - ISIS, L1 - IS-IS level-1, L2 - IS-IS level-2
                           ia - IS-IS inter area, su - IS-IS summary null, * - candidate default
                           U - per-user static route, o - ODR, L - local, G  - DAGR, l - LISP
                           A - access/subscriber, a - Application route
                           M - mobile route,   FRR Backup path
                    
                    
                    Gateway of last resort is not set
                    
                    
                    B    2001:db8::1/128
                          [200/0] via ::ffff:10.1.1.1 (nexthop in vrf default), 00:04:21
                    L    2001:db8::3/128 is directly connected,
                          00:09:01, Loopback0
                    

                     

                     

                    And a traceroute works as expected (My network is just 3 routers):

                    RP/0/0/CPU0:R3#traceroute 2001:db8::1 source 2001:db8::3
                    Fri May 31 07:06:29.266 UTC
                    
                    
                    Type escape sequence to abort.
                    Tracing the route to 2001:db8::1
                    
                    
                     1  ::ffff:10.2.3.2 [MPLS: Labels 16/19 Exp 0] 9 msec 0 msec 0 msec
                     2  2001:db8::1 0 msec 0 msec 0 msec
                    

                     

                     

                    Code versions I'm running:

                    Fri May 31 07:12:56.090 UTC
                    
                    
                    Cisco IOS XR Software, Version 5.2.2[Default]
                    Copyright (c) 2014 by Cisco Systems, Inc.
                    
                    
                    ROM: GRUB, Version 1.99(0), DEV RELEASE
                    
                    
                    R3 uptime is 24 minutes
                    System image file is "bootflash:disk0/xrvr-os-mbi-5.2.2/mbixrvr-rp.vm"
                    
                    
                    cisco IOS XRv Series (Pentium Celeron Stepping 3) processor with 3145215K bytes of memory.
                    Pentium Celeron Stepping 3 processor at 2412MHz, Revision 2.174
                    IOS XRv Chassis
                    

                     

                     

                    R1#sho version
                    *May 31 07:13:12.009: %SYS-5-CONFIG_I: Configured from console by console
                    Cisco IOS XE Software, Version 16.04.03
                    Cisco IOS Software [Everest], CSR1000V Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 16.4.3, R)
                    Technical Support: http://www.cisco.com/techsupport
                    Copyright (c) 1986-2017 by Cisco Systems, Inc.
                    Compiled Thu 14-Dec-17 08:11 by mcpre
                    
                    • 7. Re: IPv6 bgp neighbor
                      nammon

                      Thank David,

                      I really appreciate your help.