EE444HW4 - EE 444 INTRODUCTION TO COMPUTER NETWORKS Spring...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
EE 444 INTRODUCTION TO COMPUTER NETWORKS Spring 2009 HOMEWORK # 4 Deadline: April 24 2009 @ 23:59 (No late submission is allowed.) Posted on April 17 2009. Question # 1 Given the message 1010001101 and the CRC polynomial P(x) = x 5 +x 4 +x 2 +1. (a) Compute the final message to be sent including the CRC. (b) Show how the receiver performs the CRC check operation on the received message. Show all your work. Question # 2 (a) A channel has a data rate of 4 kbps and a propagation delay of 20 ms. For what range of frame sizes does stop-and-wait give an efficiency of at least 50%? (b) Two nodes n 1 and n 2 communicate using Go-Back-N as the ARQ mechanism with a window size of 4 frames. Assume that n 1 is transmitting and n 2 is receiving. Show the window positions for the following sequence of events. 1. Before n 1 sends any frames. 2. After n 1 sends frames 0, 1, 2 and n 2 acknowledges 0, 1 and the ACKs are received by n 1 . 3.
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/09/2010 for the course EE ee444 taught by Professor Akan during the Spring '10 term at Middle East Technical University.

Ask a homework question - tutors are online