Suppose that a router interconnects three subnets, where all the interfaces of the subnets must have the prefix 164.132.62/24. Also, suppose that Subnet 1 is required to support up to 60 interfaces, Subnet 2 is required to support up to 100 interfaces, and Subnet 3 is required to support up to 15 interfaces. Provide three network addresses of the form a.b.c.d/x that satisfy the above requirements.

A router interconnects a subnet, where all the interfaces of the subnets must have the prefix 164.132.62/24. suppose that the Subnet is required to support up to 60 interfaces, provide a network address that satisfies the above.

1. Consider a path from host A to host B through a router X as follows: A- -X-B The capacity of the link AX is denoted Ra, while the capacity of the link XB is denoted Rb in units of [bits/s]. Assume that Ra Ri. Is it possible that the second packet queues at input queue of the second link? Explain. Now suppose that host A sends the second packet T seconds after sending the first packet. How large must T be to ensure no queueing before the second link? Explain.

Consider transferring an enormous file of L bytes from Host A to Host B. Assume an MSS of 536 bytes. a. What is the maximum value of L such that TCP sequence numbers are not exhausted? Recall that the TCP sequence number field has 4 bytes. b. For the L you obtain in (a), find how long it takes to transmit the file. Assume that a total of 66 bytes of transport, network, and data-link header are added to each segment before the resulting packet is sent out over a 155 Mbps link. Ignore flow control and congestion control so A can pump out the segments back to back and continuously.

Compare GBN, SR, and TCP (no delayed ACK). Assume that the timeout values for all three protocols are sufficiently long such that 5 consecutive data segments and their corresponding ACKs can be received (if not lost in the channel) by the receiving host (Host B) and the sending host (Host A) respectively. Suppose Host A sends 5 data segments to Host B, and the 3rd segment (sent from A) is lost. In the end, all 5 data segments have been correctly received by Host B. How many segments has Host A sent in total and how many ACKs has Host B sent in total? What are their sequence numbers? Answer this question for all three protocols.   The previous expert did the wrong question and the answer was incorrect. The 3rd packet is lost not the 2nd packet

Suppose two TCP connections share a path through a router R. The router's queue size is six segments; each connection has a stable congestion window of three segments. No congestion control is used by these connections. A third TCP connection now is attempted, also through R. The third connection does not use congestion control either. Describe a scenario in which, for at least a while, the third connection gets none of the available bandwidth, and the first two connections proceed with 50% each. Does it matter if the third connection uses slow start? How does full congestion avoidance on the part of the first two connections help solve this?

2. Consider a slotted TDM hierarchical network in which there are 8 computers sharing a 10 Mbps channel to a router R1, sending packets to R1 which must all be forwarded by R1 over an outgoing link (called the MAN link), as shown in Figure 1. Computers A-H always have packets waiting to be sent, so no timeslot on the shared LAN is idle. Ignore the propagation delay on the LAN. The MAN link outgoing from R1 is a 100 Mbps link. The network layer protocol in use has a PDU with exactly 40 bytes of header and exactly 200 bytes of payload (SDU). The DLC layer protocol in use on the LAN has a PDU with exactly 40 bytes of header and 20 bytes of trailer. The DLC layer protocol in use on the outgoing link from R1 has a PDU with 40 bytes of header and no trailer. The physical layer does not impose any bit overhead in either channel. Use 1 Mbps = 1000000 bps. B D E F G H R1 R2 Figure 1 (a) What is the transmission delay of a bit for Computer A? (b) What is the transmission delay of a DLC PDU for…

39. The figure below shows the TCP Congestion Window for various transmission rounds of a TCP connection. 20 18 16 14 12 10 4 2 2 4 6 10 12 14 16 18 20 Transmission Round How many more (or less) segments will TCP Tahoe send compared to TCP Reno between the transmission rounds 12 and 16 inclusive (i.e., t12 to t16) for the same sequence of events as shown in the graph above (i.e., loss events at t11, tl4 and t16)? a. TCP Tahoe send 13 less segments compared to TCP Reno b. TCP Tahoe send 20 more segments compared to TCP Reno c. TCP Tahoe send 13 more segments compared to TCP Reno d. TCP Tahoe send 20 less segments compared to TCP Reno e. TCP Tahoe send 28 less segments compared to TCP Reno Congestion Window (MSS) 00

Consider a router that interconnects three subnets: Subnet 1, Subnet 2, and Subnet 3. Suppose all of the interfaces in each of these three subnets are required to have the prefix 223.10.128/24. Also suppose that Subnet 1 is required to support at least 50 interfaces, Subnet 2 is to support at least 100 interfaces, and Subnet 3 is to support at least 12 interfaces. Provide three network addresses (of the form a.b.c.d/x) that satisfy these constraints.

22. A datagram subnet allows routers to drop packets whenever they need to. The probability of a router discarding a packet is p. Consider the case of a source host connected to the source router, which is connected to the destination router, and then to the destination host. If either of the routers discards a packet, the source host eventually times out and tries again. If both host-router and router-router lines are counted as hops, what is the mean number of a. (a) hops a packet makes per transmission? b. (b) transmissions a packet makes? (c) hops required per received packet?