IP OSPF Network point-to-point
This command manually sets the OSPF network type to point-to-point. This is the default for serial links. The point-to-point network type does not have a DR election.
Note: Point-to-point can only have a single adjaceny over a link.
Router(config-if)#ip ospf network point-to-point
In this example, we will configure R1’s S1/1 to R3 to use its default network type
First, we’ll configure OSPF on R1 and R3 for their S1/1 interfaces
R1(config-router)#router ospf 1 R1(config-router)#network 0.0.0.0 0.0.0.0 area 0
Next, we’ll configure the serial link to use point-to-point.
R1(config)#int s0/0 R1(config-if)#ip ospf network point-to-point
Checking show ip ospf interface s1/1 we see the network type is point to piont
Serial1/1 is up, line protocol is up Internet Address 192.168.13.1/30, Area 0 Process ID 1, Router ID 220.127.116.11, Network Type POINT_TO_POINT, Cost: 64 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:02 Supports Link-local Signaling (LLS) Index 3/3, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 4 msec, maximum is 4 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 18.104.22.168 Suppress hello for 0 neighbor(s)
After we configure the neighbor statement, the adjacencies come up.
Notice there is no DR information in the show ip ospf neighbor output. This is because the network type doesn’t support elections
R1(config-if)#do show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 22.214.171.124 0 FULL/ – 00:00:30 192.168.13.2 Serial1/1