Computer and Communication Networks (paperback)

Consider a packet-switching network for server communications with n nodes. For each of the following topologies, sketch the network, and give the average number of hops between a pair of servers (include the server-to-node link as a hop):

1. Star: one central node with all servers attached to the central node

2. Bidirectional ring: each node connects to two other nodes to form a loop, with each node connected to one server

3. Fully connected: each node is directly connected to all other nodes, with each node connected to one server

4. A ring with n - 1 nodes connected to a central node , with each node in the ring connected to one server.

Figure 7.18 shows a network.

1. Find the least-cost path between the two servers, using Dijkstra's algorithm.

2. Show an iteration graph as the least-cost path is developed.

For the network shown in Figure 7.18:

1. Find the least-cost path between the two servers, using the Bellman-Ford algorithm.

2. Show an iteration graph as the least-cost path is developed.

Consider again the network in Figure 7.18. Assume that each link is bidirectional and that the cost of either direction is identical.

1. Find the least-cost path between the two servers, using Dijkstra's algorithm.

2. Show an iteration graph as the least-cost path is developed.

The network shown in Figure 7.19 is a snapshot of a practical consisting of seven routers. The load on each link is normalized to a number indicated on that link.

1. Find the least-cost path between the two routers R1 and R7, using Dijkstra's Algorithm.

2. Show an iteration graph as the least-cost path is developed.

For the network shown in Figure 7.19:

1. Find the least-cost path between the two servers, using the Bellman-Ford algorithm.

2. Show an iteration graph as the least-cost path is developed.

The practical network shown in Figure 7.20 is a WAN consisting of seven routers R ₁ through R ₇ interconnecting four LANs. The load on each link is normalized to a number indicated on that link. Assume that all links are bidirectional with equal indicated load.

1. Find the least-cost path between the two routers R1 and R ₇ connecting users A and B, using Dijkstra's algorithm.

2. Show an iteration graph as the least-cost path is developed.

The practical network shown in Figure 7.20 is a WAN consisting of seven routers R ₁ through R ₇ interconnecting four LANs. The load on each link is normalized to a number indicated on that link. Assume that all links are bidirectional with equal indicated load.

1. Find the least-cost path between the two routers R1 and R ₇ connecting users A and B, using Bellman-Ford's algorithm.

2. Show an iteration graph as the least-cost path is developed.

The network in Figure 7.21 has six interconnected nodes, A through F. The corresponding blocking probabilities of links are indicated on the corresponding links. For this network, find the overall blocking probability from A to F.

Figure 7.22 shows a large communication network of six interconnected nodes, A through F. The corresponding blocking probabilities of links are indicated on the corresponding links. For this network, find the overall blocking probability from AtoF.

Computer simulation project . Write a computer program to simulate Dijkstra's algorithm for the seven-node network shown in Figure 7.20. Your program must

1. Use a scheme that runs for any hypothetical link cost. Users A and B use the Bellman-Ford algorithm.

2. Compute the least-cost path between any two routers.

Computer simulation project . Write a computer program to simulate the Bellman-Ford algorithm for the seven-node network shown in Figure 7.20. Your program must

1. Use a scheme that runs for any hypothetical link cost. Users A and B use the Bellman-Ford Algorithm.

2. Compute the least-cost path between any two routers.