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Computer Networking: A Top-Down Approach
Featuring the Internet, 3rd Edition
Solutions to Review Questions and Problems

Version Date: April 26, 2005

This document contains the solutions to review questions and problems for the 3rd
edition of Computer Networking: A Top-Down Approach Featuring the Internet by Jim
Kurose and Keith Ross. These solutions are being made available toinstructors ONLY.
Please do NOT copy or distribute this document to others (even other instructors). Please
do not post any solutions on a publicly-available Web site. We’ll be happy to provide a
copy (up-to-date) of this solution manual ourselves to anyone who asks.

All material © copyright 1996-2005 by J.F. Kurose and K.W. Ross. All rights reserved

Chapter 1 Review Questions
1. There is nodifference. Throughout this text, the words “host” and “end system” are
used interchangeably. End systems include PCs, workstations, Web servers, mail
servers, Internet-connected PDAs, WebTVs, etc.
2. Suppose Alice, an ambassador of country A wants to invite Bob, an ambassador of
country B, over for dinner. Alice doesn’t simply just call Bob on the phone and say,
“come to our dinner table now”.Instead, she calls Bob and suggests a date and time.
Bob may respond by saying he’s not available that particular date, but he is available
another date. Alice and Bob continue to send “messages” back and forth until they
agree on a date and time. Bob then shows up at the embassy on the agreed date,
hopefully not more than 15 minutes before or after the agreed time. Diplomatic
protocols alsoallow for either Alice or Bob to politely cancel the engagement if they
have reasonable excuses.
3. A networking program usually has two programs, each running on a different host,
communicating with each other. The program that initiates the communication is the
client. Typically, the client program requests and receives services from the server
program.
4. The Internet provides itsapplications a connection-oriented service (TCP) and a
connectionless service (UDP). Each Internet application makes use of one these two
services. The two services will be discussed in detail in Chapter 3. Some of the
principle characteristics of the connection-oriented service are:







Two end-systems first “handshake” before either starts to send application data to
the other.Provides reliable data transfer, i.e., all application data sent by one side of the
connection arrives at the other side of the connection in order and without any
gaps.
Provides flow control, i.e., it makes sure that neither end of a connection
overwhelms the buffers in the other end of the connection by sending to many
packets to fast.
Provides congestion control, i.e., regulates the amount ofdata that an application
can send into the network, helping to prevent the Internet from entering a state of
grid lock.

The principle characteristics of connectionless service are:




No handshaking
No guarantees of reliable data transfer
No flow control or congestion control

5. Flow control and congestion control are two distinct control mechanisms with distinct
objectives.Flow control makes sure that neither end of a connection overwhelms the
buffers in the other end of the connection by sending to many packets to fast.
Congestion control regulates the amount of data that an application can send into the
network, helping to prevent congestion in the network core (i.e., in the buffers in the
network routers).
6. The Internet’s connection-oriented serviceprovides reliable data transfer by using
acknowledgements and retransmissions. When one side of the connection doesn’t
receive an acknowledgement (from the other side of the connection) for a packet it
transmitted, it retransmits the packet.
7. A circuit-switched network can guarantee a certain amount of end-to-end bandwidth
for the duration of a call. Most packet-switched networks today...
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