5.2 knowledge checks CS656

What is the definition of a "good" path for a routing protocol? Chose the best single answer. A: A path that has little or no congestion. B: Routing algorithms typically work with abstract link weights that could represent any of, or combinations of, all of the other answers. C: A path that has a minimum number of hops. D: A high bandwidth path. E: A low delay path.

B: Routing algorithms typically work with abstract link weights that could represent any of, or combinations of, all of the other answers.

Centralized, global routing

All routers have complete topology, and link cost information.

Decentralized routing.

An iterative process of computation, exchange of informatoin with neighbors. Routers may initially only know link costs to directly-attached neighbors.

Consider Dijkstra's link-state routing algorithm that is computing a least-cost path from node a to other nodes b, c, d, e, f. Which of the following statements is true

In the initialization step, the initial cost from a to each of these destinations is initialized to either the cost of a link directly connecting a to a direct neighbor, or infinity otherwise. The values computed in the vector D(v), the currently known least cost of a path from a to any node v, will never increase following an iteration. Suppose nodes b, c, and d are in the set N'. These nodes will remain in N' for the rest of the algorithm, since the least-cost paths from a to b, c, and d are known.

Static routing.

Routes change slowly over time.

dynamic routing

Routing changes quickly over time.