Question

computer networking help

4. 120 points) Consider a network with the following topology (1) Use Djikistra shortest path algorithm to find the spanning tree which contains all form router A to the rest of the routers the network. Show the first 4 steps of the results of the algorithm. (Note that unless specified in figure, all link metrics are 1.) Answer: Step N LA 3.A 2.A (2) Assume that RIP is used as the routing protocol and all link metrics are 1. Also, all routers are power up simultaneously and each router only has their immediate neighbors in tis routing table. For simplicity, assume that all routing tables are eschanged l and received at the same time. Show the routing tables of A after one and two exchnges with its neighbors aitial routing table ofA Destination Hops Next Hop After one exchanges: Next Hop Destination Hops After two exchanges: Destination Hops Next Hop

Answer 1

4(1) :

45 LU 79

ALGORITHM :
function Dijkstra(Graph, source):
       dist[source]  := 0                     // Distance from source to source is set to 0
       for each vertex v in Graph:            // Initializations
           if v ≠ source
               dist[v]  := infinity           // Unknown distance function from source to each node set to infinity
           add v to Q                         // All nodes initially in Q

      while Q is not empty:                  // The main loop
          v := vertex in Q with min dist[v]  // In the first run-through, this vertex is the source node
          remove v from Q 

          for each neighbor u of v:           // where neighbor u has not yet been removed from Q.
              alt := dist[v] + length(v, u)
              if alt < dist[u]:               // A shorter path to u has been found
                  dist[u]  := alt            // Update distance of u 

      return dist[]
  end function