Chapter 5

"Do I Know This Already?"

11.A and B


1.The ip ospf priority number command is used to determine the DR manually. The higher the priority, the greater the likelihood of winning the DR election.
2.By default, the OSPF metric is calculated as 100,000,000 bps divided by the speed of the line. For instance, a 10 Mbps Ethernet interface has a cost of 10 and a 1.544 Mbps T1 interface has a cost of 64.
3.To have more than one OSPF process on a router, simply identify two separate processes. For example:

router ospf 1

router ospf 2

You might do this to create two different domains with separate routing policies.

network area 0
network area 0
network area 0
network area 0
5.The most straightforward way to change the metric on an interface is to set the cost:
Router(config-if)# ip ospf cost cost

Cost is a 16-bit value (0 to 65,535) and lower values are preferred. A second way to deal with high-bandwidth paths is to change the numerator in the automatic calculation.

Router(config-if)# ip ospf auto-cost reference-bandwidth reference-bandwidth
 ip ospf neighbor or show ip ospf interface
7.The show ip ospf database command displays the contents of the router's topological database and the different LSAs that have populated the database ip ospf neighbor
9.debug ip packet
10.Process ID is shown by a number of commands, including

show ip ospf

show ip ospf database

show ip ospf interface

11.LSAs are labeled with sequence numbers so that they can be distinguished from each other. LSAs are marked with sequence numbers so that older or newer versions of an advertisement can be recognized. LSA sequence numbers start at 0x8000 0001 and iterate to 0xFFFF FFFF before wrapping back around to 0x0000 00000.
12.The field specifies how long to wait to start SPF after receiving an LSA to prevent running SPF too often. The default time is 5000 msec.
13.The show ip ospf interface command allows you to verify that a given interface is active in OSPF, verify its area, and look at the DR and BDR.