Last Updated on August 7, 2021 by Admin 3
You issue the show ip route command on RouterE and receive the following output:
Which of the following statements are accurate about the route to 184.108.40.206/24? (Select 2 choices.)
- The link cost is 66.
- The link cost is 110.
- The AD is 66.
- The AD is 110.
- The bandwidth of the link is 66 Kbps.
- The bandwidth of the link is 110 Kbps.
The administrative distance (AD) of the route in the scenario is 110, and the link cost is 66. In the output of the show ip route command, the first number within the brackets indicates the AD. When multiple routes to a network exist and each route uses a different routing protocol, a router prefers the routing protocol with the lowest AD. The following list contains the most commonly used ADs:
The AD of the route in this scenario is 110, the same as the default distance for an Open Shortest Path First (OSPF) route. AD for a routing protocol can be manually configured by issuing the distance command in router configuration mode. For example, to change the AD of OSPF process ID 1 from 110 to 80, you could issue the following commands:
RouterE(config)#router ospf 1 RouterE(config-router)#distance 80
The second number within the brackets indicates the metric. Because this is an OSPF link, as indicated by the O at the start of the route statement, the second number within the brackets indicates the cost metric. Therefore, the cost of the link in this scenario is 66. When two OSPF paths exist to the same destination, the router will choose the OSPF path with the lowest cost.
OSPF calculates cost based on the bandwidth of an interface: the higher the bandwidth, the lower the cost. To calculate the cost, divide 100,000,000 by the bandwidth in bits per second. Thus a 100Mbps link would have a cost of 1, a 10Mbps link would have a cost of 10, a T1 line would have a cost of 64 (100,000,000 / 1,544,000), and a 64Kbps line would have a cost of 1,562.
As the hops between a router and a destination increase, the cost increases by the bandwidth calculation of the additional links. Therefore, the route in this scenario is the cost of the FastEthernet link between RouterE and RouterC added to the cost of the T1 link between RouterC and RouterB added to the cost of the FastEthernet link between RouterB and the 220.127.116.11/24 network. Therefore, the cost for RouterE to reach the 18.104.22.168/24 network is 1 + 64 + 1, or 66.