CCNA 3 Labs and Study Guide - BINARYBB.INFO – @jagalbraith

It means that this router is running at least two different routing processes. One of them is OSPF. In this
case, the other is a static default route. This can be deduced from the “Routing Information Sources” portion
of the output. Notice that the gateway 209.165.202.129 is not listed in the “Routing for Networks”
portion of the output. This means that 209.165.202.129 is not part of OSPF but is being routed inside
OSPF from another source. In this case, the default-information originate command along with the ip
route command has made this router an ASBR (autonomous system boundary router).
What command generates the following output?
Router#debug ip ospf events
00:09:46: OSPF: Rcv hello from 192.168.1.249 area 0 from Serial0/1 192.168.1.246
00:09:46: OSPF: Mismatched hello parameters from 192.168.1.246
00:09:46: OSPF: Dead R 160 C 120, Hello R 40 C 40
00:10:26: OSPF: Rcv hello from 192.168.1.253 area 0 from Serial0/0 192.168.1.253
00:10:26: OSPF: End of hello processing
00:10:26: OSPF: Rcv hello from 192.168.1.249 area 0 from Serial0/1 192.168.1.246
00:10:26: OSPF: Mismatched hello parameters from 192.168.1.246
00:10:26: OSPF: Dead R 160 C 120, Hello R 40 C 40
00:11:06: OSPF: Rcv hello from 192.168.1.253 area 0 from Serial0/0 192.168.1.253
00:11:06: OSPF: End of hello processing
00:11:06: OSPF: Rcv hello from 192.168.1.249 area 0 from Serial0/1 192.168.1.246
00:11:06: OSPF: Mismatched hello parameters from 192.168.1.246
00:11:06: OSPF: Dead R 160 C 120, Hello R 40 C 40
00:11:46: OSPF: Rcv hello from 192.168.1.253 area 0 from Serial0/0 192.168.1.253
00:11:46: OSPF: End of hello processing
00:11:46: OSPF: Rcv hello from 192.168.1.249 area 0 from Serial0/1 192.168.1.246
00:11:46: OSPF: Mismatched hello parameters from 192.168.1.246
00:11:46: OSPF: Dead R 160 C 120, Hello R 40 C 40
00:11:46: OSPF: 192.168.1.249 address 192.168.1.246 on Serial0/1 is dead
00:11:46: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.1.249 on Serial0/1 from FULL to
DOWN, Neighbor Down: Dead timer expired
From the preceding command output, what is the problem?
In OSPF configurations, hello and dead intervals must be the same for all OSPF neighbors. In the output
shown, you interpret the line Dead R 160 C 120, Hello R 40 C 40 as follows: dead received, 160 seconds;
dead configured 120 seconds; hello received, 40 seconds; hello configured, 40 seconds.
In this case, the dead interval has been changed from 160, which was four times the hello, to 120. The reason
why you know that it has just been changed is that the local router had established adjacency with
192.168.1.249. It took the configured 120-second dead interval before the adjacency state with the neighbor
to go from FULL to DOWN.
What command would fix the “mismatch of hello parameters”?
Router(config-if)#ip ospf dead-interval 160
or
Router(config-if)#no ip ospf dead-interval 120
Chapter 3: EIGRP and Troubleshooting Routing Protocols 189