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Unformatted text preview: CS 168 Computer Networks Jannotti Homework 3 Due: 12 April 2010, 4pm Problem 1 Sec. 6, prob. 1 The LISTEN call could indicate a willingness to establish new connections but not block. When an attempt to connect was made, the caller could be given a signal. It would then execute, say, OK or REJECT to accept or reject the connection. In our original scheme, this flexibility is lacking. Sec. 6, prob. 6 Deadlocks are possible. For example, a packet arrives at A out of the blue, and A acknowledges it. The acknowledgement gets lost, but A is now open while B knows nothing at all about what has happened. Now the same thing happens to B, and both are open, but expecting different sequence numbers. Timeouts have to be introduced to avoid the deadlocks. Sec. 6, prob. 25 The entire TCP segment must fit in the 65,515-byte payload field of an IP packet. Since the TCP header is a minimum of 20 bytes, only 65,495 bytes are left for TCP data. Sec. 6, prob. 35 It takes 4 x 10 = 40 instructions to copy 8 bytes. Forty instructions takes 40 nsec on a 1000-MIPS CPU. Thus, each byte requires 5 nsec of CPU time for copying. The system is thus capable of handle 200 MB/sec or 1600 Mbps. It can handle a 1-Gbps line if no other bottleneck is present. CS 168 Homework 3 12 April 2010, 4pm Problem 2 a. There are a few solutions to this problem.a....
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- Spring '10
- Computer Networks