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Hands-On Lab: Configuring OSPF on Point-to-Point Networks

This hands-on lab configures OSPF between two routers connected via a serial point-to-point link, verifies the neighbor adjacency forms quickly without DR/BDR election, and confirms routes are exchanged correctly.

OSPF Point-to-PointNeighbor AdjacencyOSPF Network Type

~3 min read · Updated Sep 22, 2026

Lab Objective

Configure OSPF on a serial link between two routers, verify the network type is automatically recognized as point-to-point, confirm the neighbor relationship forms without requiring DR/BDR election, and verify route exchange.

Lab Purpose

OSPF behaves differently depending on the underlying network type, discussed earlier in this series regarding OSPF fundamentals. Point-to-point links are the simplest case, forming adjacencies quickly since there is no need to elect a Designated Router when only two devices can ever be present on the segment.

Lab Topology

R1 ---- Serial0/0/0 ------ Serial0/0/0 ---- R2

R1: 10.5.5.1/30, LAN 192.168.5.0/24
R2: 10.5.5.2/30, LAN 192.168.6.0/24

Task 1: Configure Basic Addressing

Configure the serial interfaces and each router's LAN.

Task 2: Enable OSPF on Both Routers

Enable OSPF process 1 on both routers, advertising all relevant networks into area 0.

Task 3: Verify the Network Type

Confirm the serial interface is automatically recognized as a point-to-point OSPF network type.

Task 4: Verify the Neighbor Relationship

Confirm the neighbor reaches FULL state, and note the absence of any DR/BDR role.

Task 5: Verify Route Exchange

Confirm each router learns the other's LAN via OSPF.

Solution and Verification

R1(config)# interface serial0/0/0
R1(config-if)# ip address 10.5.5.1 255.255.255.252
R1(config-if)# no shutdown
R1(config-if)# exit
R1(config)# interface gigabitethernet0/0
R1(config-if)# ip address 192.168.5.1 255.255.255.0
R1(config-if)# no shutdown

R2(config)# interface serial0/0/0
R2(config-if)# ip address 10.5.5.2 255.255.255.252
R2(config-if)# clock rate 64000
R2(config-if)# no shutdown
R2(config-if)# exit
R2(config)# interface gigabitethernet0/0
R2(config-if)# ip address 192.168.6.1 255.255.255.0
R2(config-if)# no shutdown

R1(config)# router ospf 1
R1(config-router)# network 10.5.5.0 0.0.0.3 area 0
R1(config-router)# network 192.168.5.0 0.0.0.255 area 0

R2(config)# router ospf 1
R2(config-router)# network 10.5.5.0 0.0.0.3 area 0
R2(config-router)# network 192.168.6.0 0.0.0.255 area 0

R1# show ip ospf interface serial0/0/0

Serial0/0/0 is up, line protocol is up
  Internet Address 10.5.5.1/30, Area 0
  Network Type POINT_TO_POINT, Cost: 64
-- Automatically detected as point-to-point,
-- since serial interfaces default to this
-- OSPF network type

R1# show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
10.5.5.2         0     FULL/  -        00:00:38    10.5.5.2        Serial0/0/0
-- Note the "-" in place of a DR/BDR role,
-- and priority 0 -- point-to-point networks
-- never elect a DR or BDR at all, since
-- with only two possible neighbors that
-- election serves no purpose

R1# show ip route ospf

O    192.168.6.0/24 [110/65] via 10.5.5.2, Serial0/0/0

Key Takeaway

Point-to-point OSPF network types skip DR/BDR election entirely, showing a dash instead of a role in the neighbor table — this is expected, normal behavior rather than a misconfiguration, and it also means adjacency typically forms faster than on broadcast-type networks like Ethernet, which must complete DR/BDR election before reaching FULL state.

Written & researched by Dr. Shahin Siami

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