Monday, June 8, 2015

BGP Prefix-Independent Convergence (VPNv4 AF)




In the below scenario, we will establish MPLS L3VPN using BGP as the PE-CE routing protocol, we will examine PIC on both address families: IPv4 and VPNv4

R1#show ip bgp
BGP table version is 3, local router ID is 1.1.1.1
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       0.0.0.0                  0         32768 i
 *>  5.5.5.5/32       192.168.12.2                           0 2 5 i

R1#ping 5.5.5.5 source lo0
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 5.5.5.5, timeout is 2 seconds:
Packet sent with a source address of 1.1.1.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 540/608/688 ms

R5#ping 1.1.1.1 source lo0
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
Packet sent with a source address of 5.5.5.5
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 488/553/624 ms

R5#show ip bgp 1.1.1.1 255.255.255.255
BGP routing table entry for 1.1.1.1/32, version 6
Paths: (2 available, best #2, table default)
  Advertised to update-groups:
     1
  Refresh Epoch 1
  2 1
    192.168.45.4 from 192.168.45.4 (4.4.4.4)
      Origin IGP, localpref 100, valid, external
      rx pathid: 0, tx pathid: 0
  Refresh Epoch 1
  2 1
    192.168.35.3 from 192.168.35.3 (3.3.3.3)
      Origin IGP, localpref 100, valid, external, best
      rx pathid: 0, tx pathid: 0x0

R5#show ip cef 1.1.1.1 255.255.255.255 detail
1.1.1.1/32, epoch 0, flags rib only nolabel, rib defined all labels
  recursive via 192.168.35.3
    attached to FastEthernet1/0
R2#show bgp vpnv4 unicast all
BGP table version is 10, 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
Route Distinguisher: 1:1 (default for vrf mssk)
 *>  1.1.1.1/32       192.168.12.1             0             0 1 i
 * i 5.5.5.5/32       4.4.4.4                  0    100      0 5 i
 *>i                  3.3.3.3                  0    100      0 5 i

R2#show bgp vpnv4 unicast all 5.5.5.5 255.255.255.255
BGP routing table entry for 1:1:5.5.5.5/32, version 10
Paths: (2 available, best #2, table mssk)
  Advertised to update-groups:
     1
  Refresh Epoch 1
  5
    4.4.4.4 (metric 2) from 4.4.4.4 (4.4.4.4)
      Origin IGP, metric 0, localpref 100, valid, internal
      Extended Community: RT:1:1
      mpls labels in/out nolabel/19
      rx pathid: 0, tx pathid: 0
  Refresh Epoch 1
  5
    3.3.3.3 (metric 2) from 3.3.3.3 (3.3.3.3)
      Origin IGP, metric 0, localpref 100, valid, internal, best
      Extended Community: RT:1:1
      mpls labels in/out nolabel/18
      rx pathid: 0, tx pathid: 0x0

R2#sh ip cef vrf mssk 5.5.5.5/32 detail
5.5.5.5/32, epoch 0, flags rib defined all labels
  recursive via 3.3.3.3 label 18
    nexthop 192.168.23.3 FastEthernet1/1

Now, let us enable PIC on R5 under the IPv4 address-family
R5
R5(config)#router bgp 5
R5(config-router)#address-family ipv4 unicast
R5(config-router-af)#bgp additional-paths install

R5#show ip bgp
BGP table version is 9, local router ID is 5.5.5.5
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
 *b  1.1.1.1/32       192.168.45.4                           0 2 1 i
 *>                   192.168.35.3                           0 2 1 i
 *>  5.5.5.5/32       0.0.0.0                  0         32768 i

R5#show ip bgp 1.1.1.1 255.255.255.255
BGP routing table entry for 1.1.1.1/32, version 8
Paths: (2 available, best #2, table default)
  Additional-path-install
  Advertised to update-groups:
     1
  Refresh Epoch 1
  2 1
    192.168.45.4 from 192.168.45.4 (4.4.4.4)
      Origin IGP, localpref 100, valid, external, backup/repair, recursive-via-connected
      rx pathid: 0, tx pathid: 0
  Refresh Epoch 1
  2 1
    192.168.35.3 from 192.168.35.3 (3.3.3.3)
      Origin IGP, localpref 100, valid, external, best , recursive-via-connected
      rx pathid: 0, tx pathid: 0x0

R5#show ip cef 1.1.1.1 255.255.255.255 detail
1.1.1.1/32, epoch 0, flags rib only nolabel, rib defined all labels
  recursive via 192.168.35.3
    attached to FastEthernet1/0
  recursive via 192.168.45.4, repair
    attached to FastEthernet1/1

Now, we will enable PIC on R2 under the VPNv4 address-family

R2
R2(config)#router bgp 2
R2(config-router)#address-family vpnv4 unicast
R2(config-router-af)#bgp additional-paths install

R2#show bgp vpnv4 unicast all
BGP table version is 12, 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
Route Distinguisher: 1:1 (default for vrf mssk)
 *>  1.1.1.1/32       192.168.12.1             0             0 1 i
 *bi 5.5.5.5/32       4.4.4.4                  0    100      0 5 i
 *>i                  3.3.3.3                  0    100      0 5 i

R2#show bgp vpnv4 unicast all 5.5.5.5 255.255.255.255
BGP routing table entry for 1:1:5.5.5.5/32, version 12
Paths: (2 available, best #2, table mssk)
  Additional-path-install
  Advertised to update-groups:
     1
  Refresh Epoch 1
  5
    4.4.4.4 (metric 2) from 4.4.4.4 (4.4.4.4)
      Origin IGP, metric 0, localpref 100, valid, internal, backup/repair
      Extended Community: RT:1:1 , recursive-via-host
      mpls labels in/out nolabel/19
      rx pathid: 0, tx pathid: 0
  Refresh Epoch 1
  5
    3.3.3.3 (metric 2) from 3.3.3.3 (3.3.3.3)
      Origin IGP, metric 0, localpref 100, valid, internal, best
      Extended Community: RT:1:1 , recursive-via-host
      mpls labels in/out nolabel/18
      rx pathid: 0, tx pathid: 0x0

R2#sh ip cef vrf mssk 5.5.5.5/32 detail
5.5.5.5/32, epoch 0, flags rib defined all labels
  recursive via 3.3.3.3 label 18
    nexthop 192.168.23.3 FastEthernet1/1
  recursive via 4.4.4.4 label 19, repair
    nexthop 192.168.24.4 FastEthernet2/0

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