Example for Configuring Basic BGP Functions

Procedure

1. Configure an IP address for each interface.

   # Configure Router A.

   <Huawei> system-view

   [Huawei] sysname RouterA

   [RouterA] interface gigabitethernet 1/0/0

   [RouterA-GigabitEthernet1/0/0] ip address 8.1.1.1 8

   [RouterA-GigabitEthernet1/0/0] quit

   The configurations of Router B, Router C, and Router D are similar to the configuration of Router A, and are not mentioned here.

2. Configure IBGP connections.

   # Configure Router B.

   [RouterB] bgp 65009

   [RouterB-bgp] router-id 2.2.2.2

   [RouterB-bgp] peer 9.1.1.2 as-number 65009

   [RouterB-bgp] peer 9.1.3.2 as-number 65009

   # Configure Router C.

   [RouterC] bgp 65009

   [RouterC-bgp] router-id 3.3.3.3

   [RouterC-bgp] peer 9.1.3.1 as-number 65009

   [RouterC-bgp] peer 9.1.2.2 as-number 65009

   [RouterC-bgp] quit

   # Configure Router D.

   [RouterD] bgp 65009

   [RouterD-bgp] router-id 4.4.4.4

   [RouterD-bgp] peer 9.1.1.1 as-number 65009

   [RouterD-bgp] peer 9.1.2.1 as-number 65009

   [RouterD-bgp] quit

3. Configure an EBGP connection.

   # Configure Router A.

   [RouterA] bgp 65008

   [RouterA-bgp] router-id 1.1.1.1

   [RouterA-bgp] peer 200.1.1.1 as-number 65009

   # Configure Router B.

   [RouterB-bgp] peer 200.1.1.2 as-number 65008

   # View the status of BGP peers.

   [RouterB-bgp] display bgp peer

    BGP local router ID : 2.2.2.2

    Local AS number : 65009

    Total number of peers : 3                 Peers in established state : 3

     Peer          V    AS  MsgRcvd  MsgSent  OutQ  Up/Down         State PrefRcv

     9.1.1.2       4 65009       49       62     0 00:44:58 Established       0

     9.1.3.2       4 65009       56       56     0 00:40:54 Established       0

     200.1.1.2     4 65008       49       65     0 00:44:03 Established       1

   The preceding command output shows that BGP connections have been established between Router B and other Routers.

4. Configure Router A to advertise route 8.0.0.0/8.

   # Configure Router A to advertise a route.

   [RouterA-bgp] ipv4-family unicast

   [RouterA-bgp-af-ipv4] network 8.0.0.0 255.0.0.0

   [RouterA-bgp-af-ipv4] quit

   # View the routing table of Router A.

   [RouterA-bgp] display bgp routing-table

    BGP Local router ID is 1.1.1.1
    Status codes: * - valid, > - best, d - damped,
                  h - history,  i - internal, s - suppressed, S - Stale
                  Origin : i - IGP, e - EGP, ? - incomplete
   
   
    Total Number of Routes: 1
         Network            NextHop        MED        LocPrf    PrefVal Path/Ogn
   
    *>   8.0.0.0        0.0.0.0            0                     0      i
   

   # View the routing table of Router B.

   [RouterB-bgp] display bgp routing-table

    BGP Local router ID is 2.2.2.2
    Status codes: * - valid, > - best, d - damped,
                  h - history,  i - internal, s - suppressed, S - Stale
                  Origin : i - IGP, e - EGP, ? - incomplete
   
   
    Total Number of Routes: 1
         Network            NextHop        MED        LocPrf    PrefVal Path/Ogn
   
    *>   8.0.0.0        200.1.1.2          0                     0      65008i
   

   # View the routing table of Router C.

   [RouterC] display bgp routing-table

    BGP Local router ID is 3.3.3.3
    Status codes: * - valid, > - best, d - damped,
                  h - history,  i - internal, s - suppressed, S - Stale
                  Origin : i - IGP, e - EGP, ? - incomplete
   
   
    Total Number of Routes: 1
         Network            NextHop        MED        LocPrf    PrefVal Path/Ogn
   
      i  8.0.0.0        200.1.1.2          0          100        0      65008i
   

   The preceding command output shows that Router C has learned the route to destination 8.0.0.0 in AS 65008. The route, however, is invalid because the next hop 200.1.1.2 of this route is unreachable.

5. Configure BGP to import direct routes.

   # Configure Router B.

   [RouterB-bgp] ipv4-family unicast

   [RouterB-bgp-af-ipv4] import-route direct

   # View the BGP routing table of Router A.

   [RouterA-bgp] display bgp routing-table

    BGP Local router ID is 1.1.1.1
    Status codes: * - valid, > - best, d - damped,
                  h - history,  i - internal, s - suppressed, S - Stale
                  Origin : i - IGP, e - EGP, ? - incomplete
   
   
    Total Number of Routes: 4
         Network            NextHop        MED        LocPrf    PrefVal Path/Ogn
   
    *>   8.0.0.0            0.0.0.0         0                     0      i
    *>   9.1.1.0/24         200.1.1.1       0                     0      65009?
    *>   9.1.3.0/24         200.1.1.1       0                     0      65009?
         200.1.1.0          200.1.1.1       0                     0      65009?
    

   # View the BGP routing table of Router C.

   [RouterC] display bgp routing-table

    BGP Local router ID is 3.3.3.3
    Status codes: * - valid, > - best, d - damped,
                  h - history,  i - internal, s - suppressed, S - Stale
                  Origin : i - IGP, e - EGP, ? - incomplete
   
   
    Total Number of Routes: 4
         Network            NextHop        MED        LocPrf    PrefVal Path/Ogn
   
    *>i  8.0.0.0          200.1.1.2       0          100        0      65008i
    *>i  9.1.1.0/24         9.1.3.1         0          100        0      ?
      i  9.1.3.0/24         9.1.3.1         0          100        0      ?
    *>i  200.1.1.0          9.1.3.1         0          100        0      ?
   

   The preceding command output shows that the route to destination 8.0.0.0 becomes valid because the next-hop address of this route is the address of Router A.

   # Run the ping command on Router C.

   [RouterC] ping 8.1.1.1

     PING 8.1.1.1: 56  data bytes, press CTRL_C to break

       Reply from 8.1.1.1: bytes=56 Sequence=1 ttl=254 time=31 ms

       Reply from 8.1.1.1: bytes=56 Sequence=2 ttl=254 time=47 ms

       Reply from 8.1.1.1: bytes=56 Sequence=3 ttl=254 time=31 ms

       Reply from 8.1.1.1: bytes=56 Sequence=4 ttl=254 time=16 ms

       Reply from 8.1.1.1: bytes=56 Sequence=5 ttl=254 time=31 ms

     --- 8.1.1.1 ping statistics ---

       5 packet(s) transmitted

       5 packet(s) received

       0.00% packet loss

       round-trip min/avg/max = 16/31/47 ms