Question

Assume Alice, the client, creates a connection with Bob, the server. They exchange data and close the connection. Now Alice starts a new connection with Bob by sending a new SYN segment. Before Bob responds to this SYN segment, a duplicate copy of the old SYN segment from Alice, which is wandering in the network, arrives at Bob's computer, initiating a SYN + ACK segment from Bob. Can this segment be mistaken by Alice's computer as the response to the new SYN segment? Explain.

Answer 1

The duplicate copy of the old SYN segment can be mistaken as the response to the new SYN segment, causing confusion in establishing the new connection between Alice and Bob.

Step-by-step explanation:

When Alice starts a new connection with Bob by sending a new SYN segment, Bob's computer expects to receive a response to the new SYN segment. However, if a duplicate copy of the old SYN segment from Alice arrives at Bob's computer before it can respond to the new SYN segment, it can cause confusion.

Alice's computer may mistakenly interpret the SYN + ACK segment initiated by the duplicate old SYN segment as the response to the new SYN segment. This is because both the new SYN segment and the duplicate old SYN segment have the same source and destination addresses, and the same sequence number. So, Alice's computer may wrongly consider the duplicate SYN + ACK segment as the response to the new SYN segment.

In summary, the duplicate copy of the old SYN segment can be mistaken by Alice's computer as the response to the new SYN segment, leading to confusion in establishing the new connection between Alice and Bob.