計(jì)算機(jī)網(wǎng)絡(luò)自頂向下方法第五版答案

1、 Computer Networking: A Top-Down Approach Featuring the Internet, 5th Edition Solutions to Review Questions and Problems Version Date: 1 September 2009 This document contains the solutions to review questions and proble

2、ms for the 5th edition of Computer Networking: A Top-Down Approach Featuring the Internet by Jim Kurose and Keith Ross. These solutions are being made available to instructors ONLY. Please do NOT copy or distribute

3、 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.

4、 Acknowledgments: Over the years, several students and colleagues have helped us prepare this solutions manual. Special thanks goes to Honggang Zhang, Rakesh Kumar, and Prithula Dunghel. All material © copyright

5、1996-2009 by J.F. Kurose and K.W. Ross. All rights reserved 10. There are two most popular wireless Internet access technologies today: a) Wireless LAN In a wireless LAN, wireless users transmit/receive packets to/from

6、a base station (wireless access point) within a radius of few tens of meters. The base station is typically connected to the wired Internet and thus serves to connect wireless users to the wired network. b) Wide-area wir

7、eless access network In these systems, packets are transmitted over the same wireless infrastructure used for cellular telephony, with the base station thus being managed by a telecommunications provider. This provides w

8、ireless access to users within a radius of tens of kilometers of the base station. 11. A circuit-switched network can guarantee a certain amount of end-to-end bandwidth for the duration of a call. Most packet-switched n

9、etworks today (including the Internet) cannot make any end-to-end guarantees for bandwidth. 12. In a packet switched network, the packets from different sources flowing on a link do not follow any fixed, pre-defined p

10、attern. In TDM circuit switching, each host gets the same slot in a revolving TDM frame. 13. At time t0 the sending host begins to transmit. At time t1 = L/R1, the sending host completes transmission and the entire pa

11、cket is received at the router (no propagation delay). Because the router has the entire packet at time t1, it can begin to transmit the packet to the receiving host at time t1. At time t2 = t1 + L/R2, the router compl

12、etes transmission and the entire packet is received at the receiving host (again, no propagation delay). Thus, the end-to-end delay is L/R1 + L/R2. 14. A tier-1 ISP connects to all other tier-1 ISPs; a tier-2 ISP conne

13、cts to only a few of the tier-1 ISPs. Also, a tier-2 ISP is a customer of one or more tier-1. 15. a) 2 users can be supported because each user requires half of the link bandwidth. b) Since each user requires 1Mbps wh

14、en transmitting, if two or fewer users transmit simultaneously, a maximum of 2Mbps will be required. Since the available bandwidth of the shared link is 2Mbps, there will be no queuing delay before the link. Whereas, if

15、three users transmit simultaneously, the bandwidth required will be 3Mbps which is more than the available bandwidth of the shared link. In this case, there will be queuing delay before the link. c) Probability that a