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Unformatted text preview: Homework Assignment #3 Due 11:59pm, November 20th EE122 Fall 2011 Please submit your solutions using BSpace (https://bspace.berkeley.edu/). Log in to BSpace with your CalNet ID, click on the EL ENG 122 Fa11 tab, and click on Assignments under Course Tools. Assignments should be submitted in one of the following formats: .txt, .pdf, or .ps. 1 1. TCP Basics: [10 points] i) A TCP connection has been established between hosts A and B. A receives a packet from B with the following field values shown below: Sequence: 1001 Acknowledgement: 5001 Window size: 3000 [TCP Payload Size: 52] Note: the size of the TCP payload is not a field, but is the number of bytes in the TCP payload, which the receiver can determine from the header lengths and total length, so we treat it here as something that can be determined from the headers. Which of the following are possible valid responses from A? (i.e., which represent TCP packets A might generate immediately after receiving this packet?) Answer: ____ a,c _________ (there can be more than one valid response) a) Sequence: 5001 Acknowledgement: 1053 Window size: 2000 [TCP Payload Size: 1000] b) Sequence: 1053 Wrong sequence number (in wrong direction) Acknowledgement: 5001 Window size: 3000 [TCP Payload Size: 1000] c) Sequence: 6001 Acknowledgement: 1053 Window size: 2000 [TCP Payload Size: 1000] d) Sequence: 8001 Beyond window size Acknowledgement: 1053 Window size: 2000 [TCP Payload Size: 1000] e) Sequence: 4001 Already ACK'd Acknowledgement: 1053 Window size: 2000 [TCP Payload Size: 1000] 2 ii) Client A initiates a Telnet session with server S, using an ephemeral source port of 45644. Client B initiates a HTTP session with server S, using an ephemeral source port of 52125. Fill in the source and destination ports for the following TCP segments: Sent from A to S: source port_ 45644 _, destination port__23____ Sent from S to A: source port___23___, destination port_45644_ Sent from B to S: source port_52125_, destination port___80___ Sent from S to B: source port___80___, destination port_52125_...
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This note was uploaded on 01/09/2012 for the course ELECTRICAL 122 taught by Professor Shenker during the Spring '11 term at University of California, Berkeley.
- Spring '11