Answer to Question #221502 in Computer Networks for Philippe COBAT

Question

Answer the following in your own words.  

1. Why does the maximum packet lifetime have to be large enough to ensure that not only the packet but also its acknowledgments have disappeared?
2. Give one potential disadvantage when Nagle's algorithm is used on a badly congested network.
3. Give two examples of cases where TCP sends data-less packets on an established connection (which is not being torn down).
4. Exercise 5.0 from section 12.24 of the textbook:
5. Suppose you see multiple TCP connections on your workstation in state FIN_WAIT_1. What is likely going on? Whose fault is it?
6. What might be going on if you see connections languishing in state FIN_WAIT_2?

Answer 1

1.So as to ensure that both the parket and its ACK is received before being discarded. In a situation where the packet is received and ACK is not received.It may lead to duplicate packets.

2.It results to increased latency which causes a delay in the application that requires a fast network response.

3(a) When using an idle established connection, a node might send up empty packets at regular intervals to ensure that the connection is still valid. if it is, the other node will response with an acknowledgment.

(b)A TCP packet with an RST bit is sent without data when their is a problem with the established connection.

5.FIN-WAIT-1, refers to where the first step of an active close four-way handshake was performed. A connection termination request has been received by the remote end-point from the local end-point. FIN-WAIT-2 means that, the remote end-point has sent an ACK for the previously already sent connection termination req. The local end-point waits for an active connection termination request from the remotefar end-point. FIN_WAIT_2, TIME_WAIT and CLOSE_WAIT are generally used. They are all related to the connection

6.FIN_WAIT_2 occurs when the server has an active connection with a client and wants to shut down the TCP connection