HDLC in conjunction with IP unnumbered interface configuration example
Network requirements
As shown in Figure 74, Router A and Router B are connected through their POS ports with HDLC enabled.
Configure POS 5/0 of Router A to borrow the IP address of the local loopback interface, whose IP address has a 32-bit mask.
Configure Router A to learn the routing information of Router B through static routes, so that Router A can reach the network segment 12.1.2.0/24.
Figure 74: Network diagram
![](images/image70.png)
Configuration procedure
Configure Router A:
<RouterA> system-view [RouterA] interface loopback 1 [RouterA-LoopBack1] ip address 12.1.1.2 32 [RouterA-LoopBack1] quit [RouterA] interface pos 5/0 [RouterA-Pos5/0] clock master [RouterA-Pos5/0] link-protocol hdlc [RouterA-Pos5/0] ip address unnumbered interface loopback 1 [RouterA-Pos5/0] quit
Configure Router B:
<RouterB> system-view [RouterB] interface pos 5/0 [RouterB-Pos5/0] link-protocol hdlc [RouterB-Pos5/0] ip address 12.1.1.1 24
Configure a static route on Router A:
[RouterA] ip route-static 12.1.1.0 24 pos 5/0 [RouterA] ip route-static 12.1.2.0 24 12.1.1.1
Verify that Router A can ping network segment 12.1.2.0/24:
[RouterA] ping 12.1.2.1 PING 12.1.2.1: 56 data bytes, press CTRL_C to break Reply from 12.1.2.1: bytes=56 Sequence=1 ttl=255 time=35 ms Reply from 12.1.2.1: bytes=56 Sequence=2 ttl=255 time=1 ms Reply from 12.1.2.1: bytes=56 Sequence=3 ttl=255 time=10 ms Reply from 12.1.2.1: bytes=56 Sequence=4 ttl=255 time=1 ms Reply from 12.1.2.1: bytes=56 Sequence=5 ttl=255 time=1 ms --- 12.1.2.1 ping statistics --- 5 packet(s) transmitted 5 packet(s) received 0.00% packet loss round-trip min/avg/max = 1/9/35 ms
# Execute the display ip routing-table command on Router A to see that the routing table information is correct.
[RouterA] display ip routing-table Routing Tables: Public Destinations : 5 Routes : 5 Destination/Mask Proto Pre Cost NextHop Interface 12.1.1.0/24 Static 60 0 12.1.1.2 POS5/0 12.1.1.2/32 Direct 0 0 127.0.0.1 InLoop0 12.1.2.0/24 Static 60 0 12.1.1.1 POS5/0 127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0 127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0