Consider the subnet in Fig. 3.11.5. Distance vector routing is used and the following vectors have just come in to router C: from B (5, 0, 8, 12, 6, 2); from D(16, 12, 06, 0, 9, 10) and from E(7, 6, 3, 9, 0, 4). The measured delays to B, D and E are 6, 3 and 5 respectively. What is C's new routing table? Give both the outgoing line to used and the expected delay ? A B E Fig. 3.11.5 C F D

4. a) Consider designing an ATM network with a leaky-bucket policer that ensures a virtual circuit does not send more cells than expected. Suppose a link has a first-in-first-out (FIFO) queue and carries traffic for two virtual circuits. The traffic on the first virtual circuit follows a leaky- bucket policer (with a bucket depth of 9 cells and a token rate of 100 cells/second) and can settle for best-effort service. The traffic on the second virtual circuit follows a leaky-bucket policer (with a bucket depth of one cell and a token rate of 100 cells/second) that cannot tolerate more than 100 milliseconds of delay in delivering each cell. Suppose the propagation delay on the link is 50 milliseconds. Analyse the smallest transmission rate R, in cells per second, that can satisfy the delay constraint, given that the link serves cells in FIFO order.

A TCP connection is established through 10 wireless hops in an acoustic underwater ad hoc network. Assume that each hop is 100 meter in the average, acoustic signals travel 1500 meter per second, 10 kilobit data can be sent per second over a link, the source node has one megabyte of data to send, the receiver window size is 64 kilobytes, the maximum segment size is 1 kilobyte and the average processing delay for routing at each node is one millisecond. Assume also that the following segments do not reach the destination: 67, 112, 137. What would be the average utilization of the links for this connection if there is not another communications through them? Explain an alternative approach to increase the bandwidth utilization?

1) What is B’s new routing table? (proof is needed)    2) Give the outgoing lines to reach each destination of the network except B.

A 3 5 сл 2 B 1 3 E F 7. Consider the network from the problem running distance-vector routing has already achieved convergence. At some time link B-C fails. a) Give the routing tables at A and D after B and C have reported the news. b) Give the routing tables at A and D after their next mutual exchange.