Dynamic Routing I

The goals of any dynamic routing protocol are (select three):

• When routes in the table are no longer valid, remove them from the routing table

• Use an alternate route if an existing route is removed from the table

• Prevent routing loops, i.e. to prevent routers having inconsistent views of the network

• Manually fill in the routing table with a route to all networks in the overall internet.

In a Distance Vector routing protocol (select three):

• Each router maintains a map of the overall network and update it when changes happen

• Each router passes on its routing table to its neighboring routers

• Neighboring routers integrate this information into their own routing tables

• Neighboring routers, in turn pass their updated routing tables on to their neighbors and the process repeats

In distance vector routing protocol (select two):

• The routing table is just like a highway sign board that shows the identity of remote cities, the distance to each city and the direction you should take to reach them

• The routing table gives you the complete path to take to reach the destination

• Distance vector routers have complete knowledge of the entire network

• Distance vector routers do not have complete knowledge of the entire network

In distance vector protocol, routing advertisements carry the following information:

• Network, Via. Mask

• Network, Mask, Cost

• Network, Cost, Via

• Network, Mask, Via

What do you understand by the term "Split Horizon" ?

• If a router learns about a network from its neighbor, it must advertise this information back to the same router after 240 seconds

• If a router learns about a network from its neighbor, it must advertise this information back to the same router after 180 seconds

• If a router learns about a network from its neighbor, it must never advertise this information back to the same router

• If a router learns about a network from its neighbor, it must immediately pass this information back to the same router

What do you understand by the term "Flush Timer" ?

• The time interval after which a router will update a particular route if it an update is received on that route

• The time interval after which a router will remove a particular route if an update has not been received about that route

• The time interval after which a router passes updated information to its neighbors

• The time interval after which a router removes all routing information from its routing table

Select all of statements that are relevant to the term "Hold-down-timers" (select two)?

• If no route update has been received in 240 seconds, the router can treat the missing routes as "suspicious".

• If no route update has been received in 180 seconds, the router can treat the missing routes as "suspicious".

• Router will not advertise the suspicious routes to other routers, but it will keep using them itself

• Routers will advertise suspicious routes to other routers, but it will not use them itself

Select all of the statements below that are relevant to the term "Route Poisoning" (select three):

• The route poisoning technique does not help the network to reach convergence more quickly

• When routes disappear, instead of not telling its neighbors, the missing route is poisoned with the cost value of "infinity"

• The poisoned route is passed on quickly, instead of each router having to wait for their hold-down timers to expire

• The route poisoning technique helps the network to reach convergence more quickly

What is the operation concept of "Split Horizon with Poison Reverse"

• If a router learns a route from a neighbor, it must not advertise this back to its neighbor

• If a router learns a route from a neighbor, it must advertise this back to its neighbor but with an infinite cost

• If a route disappears this route is poisoned with a cost value of "infinity".

• Poisoned route now is passed on quickly, instead of each router having to wait for their hold-down timers to expire.

What are the flaws in class-full routing (select three) ?

• There are only three sizes of networks: /8, /16 and /24

• If you want to set up a WAN link between two routers, it has to be a /30 (Class-C) network

• if routes are learned dynamically, routers have to assume the network size is either /8, /16 or /24.

• Routers can get confused with route advertisements because they have to assume the network size (discontinuous networks)