OSPF - Routing Protocols and Concepts - page 524

Use the show ip ospf neighbor command on R1 to view the Dead Time counter.

Step 3.

The Dead Time counter is counting down from the default interval of 40 seconds:

R1# show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
10.2.2.2 0 FULL/- 00:00:34 192.168.10.2 Serial0/0/0
10.3.3.3 0 FULL/- 00:00:34 192.168.10.6 Serial0/0/1

Configure the OSPF Hello and Dead intervals. Step 4.

The OSPF Hello and Dead intervals can be modified manually using the ip ospf hello-
interval and ip ospf dead-interval interface commands. Use these commands to change
the Hello interval to 5 seconds and the Dead interval to 20 seconds on the Serial 0/0/0
interface of the R1 router:

R1(config)# interface serial0/0/0
R1(config-if)# ip ospf hello-interval 5
R1(config-if)# ip ospf dead-interval 20
R1(config-if)#
01:09:04: %OSPF-5-ADJCHG: Process 1, Nbr 10.2.2.2 on Serial0/0/0 from FULL
to DOWN, Neighbor Down: Dead timer expired
01:09:04: %OSPF-5-ADJCHG: Process 1, Nbr 10.2.2.2 on Serial0/0/0 from FULL
to Down: Interface down or detached
After 20 seconds, the Dead Timer on R1 expires. R1 and R2 lose adjacency because the
Dead Timer and Hello Timer must be configured identically on each side of the serial link
between R1 and R2.

Modify the Dead Timer and Hello Timer intervals. Step 5.

Modify the Dead Timer and Hello Timer intervals on the Serial 0/0/0 interface of the R2
router to match the intervals configured on the Serial 0/0/0 interface of the R1 router:

R2(config)# interface serial0/0/0
R2(config-if)# ip ospf hello-interval 5
R2(config-if)# ip ospf dead-interval 20
R2(config-if)#
01:12:10: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.1.1 on Serial0/0/0 from
EXCHANGE to FULL, Exchange Done
Notice that IOS displays a message when adjacency has been established with a state of Full.

Use the show ip ospf interface serial0/0/0 command to verify that the Hello Timer and
Dead Timer intervals have been modified.

Step 6.

R2# show ip ospf interface serial0/0/0
=Serial0/0/0 is up, line protocol is up
Internet address is 192.168.10.2/30, Area 0
Process ID 1, Router ID 10.2.2.2, Network Type POINT-TO-POINT, Cost: 65535
Transmit Delay is 1 sec, State POINT-TO-POINT,
Timer intervals configured, Hello 5, Dead 20, Wait 20, Retransmit 5
Hello due in 00:00:00
Index 3/3, flood queue length 0