Comunicaciones

SOLUTIONS MANUAL
DATA AND COMPUTER COMMUNICATIONS
Seventh Edition

WILLIAM STALLINGS

Copyright 2003: William Stallings

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© 2003 by William Stallings All rights reserved. No part of this document may be reproduced, in any form or by any means, or posted on the Internet, without permission in writing from the author

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NOTICE

This manual contains solutions to all ofthe review questions and homework problems in Data and Computer Communications, Seventh Edition. If you spot an error in a solution or in the wording of a problem, I would greatly appreciate it if you would forward the information via email to me at ws@shore.net. An errata sheet for this manual, if needed, is available at ftp://shell.shore.net/members/w/s/ws/S/ W.S.

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4 TABLE OF CONTENTSChapter 2: Chapter 3: Chapter 4: Chapter 5: Chapter 6: Chapter 7: Chapter 8: Chapter 9: Chapter 10: Chapter 11: Chapter 12: Chapter 13: Chapter 14: Chapter 15: Chapter 16: Chapter 17: Chapter 18: Chapter 19: Chapter 20: Chapter 21: Chapter 22:

Protocol Architecture...................................................................................5 Data Transmission.......................................................................................8 Guided and Wireless Transmission.........................................................12 Signal Encoding Techniques.....................................................................16 Digital Data Communication Techniques ..............................................24 Data LinkControl.......................................................................................31 Multiplexing................................................................................................38 Spread Spectrum ........................................................................................43 Circuit Switching and Packet Switching.................................................46 Asynchronous TransferMode..................................................................50 Routing in Switched Networks................................................................56 Congestion Control in Switched Data Networks..................................62 Cellular Wireless Networks......................................................................65 Local Area NetworkOverview................................................................69 High-Speed LANs......................................................................................77 Wireless LANs............................................................................................82 Internetwork Protocols..............................................................................84 Internetwork Operation............................................................................91 Transport Protocols....................................................................................96 Network Security .....................................................................................102 Distributed Applications.........................................................................106

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CHAPTER 2 PROTOCOL ARCHITECTURE ANSWERS
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2.1 The network access layer is concerned with the exchange of data between a computer and the network to which it is attached. 2.2 The transport layer is concerned with data reliability and correct sequencing. 2.3 A protocol is the set of rules or conventions governing the way in which two entities cooperate to exchange data. 2.4 A PDU is the combination of data from thenext higher communications layer and control information. 2.5 The software structure that implements the communications function. Typically, the protocol architecture consists of a layered set of protocols, with one or more protocols at each layer. 2.6 Transmission Control Protocol/Internet Protocol (TCP/IP) are two protocols originally designed to provide low level support for internetworking....