Which parameter would you tune to affect the selection of a static route as a backup, when a dynamic protocol is also being used?
A. hop count B. administrative distance C. link bandwidth D. link delay E. link cost
Correct Answer: B
By default the administrative distance of a static route is 1, meaning it will be preferred over all dynamic routing protocols. If you want to have the dynamic routing protocol used and have the static route be used only as a backup, you need to increase the AD of the static route so that it is higher than the dynamic routing protocol.
What is the default administrative distance of OSPF?
A. 90 B. 100 C. 110 D. 120
Correct Answer: C
Explanation: Administrative distance is the feature that routers use in order to select the best path when there are two or more different routes to the same destination from two different routing protocols. Administrative distance defines the reliability of a routing protocol. Each routing protocol is prioritized in order of most to least reliable (believable) with the help of an administrative distance value.
Default Distance Value Table
This table lists the administrative distance default values of the protocols that Cisco supports:
A router has learned three possible routes that could be used to reach a destination network. One route is from EIGRP and has a composite metric of 20514560. Another route is from OSPF with a metric of 782. The last is from RIPv2 and has a metric of 4. Which route or routes will the router install in the routing table?
A. the OSPF route B. the EIGRP route C. the RIPv2 route D. all three routes E. the OSPF and RIPv2 routes
Correct Answer: B
When one route is advertised by more than one routing protocol, the router will choose to use the routing protocol which has lowest Administrative Distance. The Administrative Distances of popular routing protocols are listed below: