Exercise 8 |
1. (2) Imagine that a two-way handshake rather than a three-way handshake were used to set up TCP connections. In other words, the third message was not required. Without timers, deadlocks are now possible. Give an example.
2. (1) Where is datagram fragmentation and reassembly handled? By IP or TCP? Why does this make sense?
3. (4) Suppose that a IP datagram with identification number
112 with 3000 data bytes passes through two networks on its way to a
destination. Each network uses the minimum IP header. Network 1 is limited to
1500 byte packets maximum and network 2 is limited to 1000 byte maximum packets.
For each packet fragment arriving at the destination list the a) identification
number, b) fragment offset, c) the boolean values of DF and MF.
4. (1) Why is the maximum TCP segment 65515 bytes?
5. (1) Examine IP format and UDP format. Why is UDP
needed if a user is only interested in sending datagrams?
6. (1) The Berkley Sockets define an accept function which blocks until a connection arrives. Would it make sense to have a nonblocking accept? Why or why not.
7. (3) Suppose that a TCP receiver advertised a window of 4096 bytes and a segment of 1024 bytes.
a) What is the maximum number of unacknowledged segments allowed?
b) When a full window is received what does the receiver do?
c) The receiver buffer fills and it sends a window size announcement of 0. The buffer is emptied by the application and a window advertisement packet is sent but lost. What happens to prevent deadlock?
8. (2) A TCP machine is sending windows of 2000 bytes over a 100-Mbps channel that has a 10-msec one-way delay.
a) What is the maximum throughput achievable?
b) What is the line efficiency?
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