1: | What is the basic application of the SPF algorithm? |
A: | The SPF algorithm was designed to find the shortest distance between two points in any problem that can be modeled as a graph. |
2: | What is a directed graph, and how is an internetwork modeled as a directed graph? |
A: | A directed graph or digraph consists of the set of vertices and the set of interconnections between the vertices referred to as arcs or directed edges. An internetwork is modeled as a directed graph by representing the network nodes or routers as vertices and the network links (adjacencies) as arcs. Bidirectional traffic flow is depicted by parallel opposite arrows. |
3: | Name the three lists used in the operation of the Dijkstra algorithm for computing IS-IS routes. |
A: | Paths, Tentative, and Unknown. |
4: | What is the estimated processing cost of the Dijkstra algorithm? |
A: | The computational cost directly dependent on the complexity of execution of Dijkstra algorithm, which is of the order, O( L log N ), where L is the number of links and N is the number of nodes. |
5: | What is the difference between a full SPF and a partial route calculation (PRC)? |
A: | A full SPF is a complete computation of the shortest path tree (SPT) caused by an adjacency change. PRC is a partial computation of the SPF algorithm and performed when only an IP prefix change is reported in a new LSP. |