The EBGP peers, Router A and Router B (usually in different ISPs), are located in different ASs. Typically,
their loopback interfaces are not reachable to each other, so directly connected interfaces are used for
establishing BGP sessions. To enable Router C to access the network 8.1.1.0/24 connected directly to
Router A, inject network 8.1.1.0/24 to the BGP routing table of Router A.
Configuration procedure
Configure IP addresses for interfaces. (Details not shown.)
1.
2.
Configure IBGP:
# Configure Router B.
<RouterB> system-view
[RouterB] bgp 65009
[RouterB-bgp] router-id 2.2.2.2
[RouterB-bgp] peer 3.3.3.3 as-number 65009
[RouterB-bgp] peer 3.3.3.3 connect-interface loopback 0
[RouterB-bgp] address-family ipv4 unicast
[RouterB-bgp-ipv4] peer 3.3.3.3 enable
[RouterB-bgp-ipv4] quit
[RouterB-bgp] quit
[RouterB] ospf 1
[RouterB-ospf-1] area 0
[RouterB-ospf-1-area-0.0.0.0] network 2.2.2.2 0.0.0.0
[RouterB-ospf-1-area-0.0.0.0] network 9.1.1.1 0.0.0.255
[RouterB-ospf-1-area-0.0.0.0] quit
[RouterB-ospf-1] quit
# Configure Router C.
<RouterC> system-view
[RouterC] bgp 65009
[RouterC-bgp] router-id 3.3.3.3
[RouterC-bgp] peer 2.2.2.2 as-number 65009
[RouterC-bgp] peer 2.2.2.2 connect-interface loopback 0
[RouterC-bgp] address-family ipv4 unicast
[RouterC-bgp-ipv4] peer 2.2.2.2 enable
[RouterC-bgp-ipv4] quit
[RouterC-bgp] quit
[RouterC] ospf 1
[RouterC-ospf-1] area 0
[RouterC-ospf-1-area-0.0.0.0] network 3.3.3.3 0.0.0.0
[RouterC-ospf-1-area-0.0.0.0] network 9.1.1.0 0.0.0.255
[RouterC-ospf-1-area-0.0.0.0] quit
[RouterC-ospf-1] quit
[RouterC] display bgp peer ipv4
BGP local router ID : 3.3.3.3
Local AS number : 65009
Total number of peers : 1
Peer
Peers in established state : 1
AS
MsgRcvd
MsgSent OutQ PrefRcv Up/Down
249
State