COMPLETE TEST BANK: computer networking: a top-down approach 7th edition by james kurose (author)latest update

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,Computer Networking: A Top-Down Approach,
th
7 Edition

Solutions to Review Questions and Problems



Version Date: December 2016



Thisqdocumentqcontainsqtheqsolutionsqtoqreviewqquestionsqandqproblemsqforqtheq7thq edit
ionqofqComputerqNetworking:qAqTop-
DownqApproachqbyqJimqKuroseqandqKeithqRoss.qTheseqsolutionsqareqbeingqmadeqavaila
bleqtoqinstructorsqONLY.q PleaseqdoqNOTqcopyqorqdistributeqthisqdocumentqtoqothersq(e
venqotherqinstructors).q Pleaseqdoqnotqpostqanyqsolutionsqonqaqpublicly-
availableqWebqsite.qWe’llqbeqhappyqtoqprovideqaqcopyq(up-to-
date)qofqthisqsolutionqmanualqourselvesqtoqanyoneqwhoqasks.


Acknowledgments:qOverqtheqyears,qseveralqstudentsqandqcolleaguesqhaveqhelpedqusq prep
areqthisqsolutionsqmanual.qSpecialqthanksqgoesqtoqHonggangqZhang,qRakeshqKumar,qPri
thulaqDhungel,qandqVijayqAnnapureddy.qAlsoqthanksqtoqallqtheqreadersqwhoqhaveqmadeq
suggestionsqandqcorrectedqerrors.




Allqmaterialq©qcopyrightq1996-2016qbyqJ.F.qKuroseqandqK.W.qRoss.qAllqrightsqreserved




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,Chapterq1qReviewqQuestions
1. Thereqisqnoqdifference.qThroughoutqthisqtext,qtheqwordsq“host”qandq“endqsystem”qar
equsedqinterchangeably.qEndqsystemsqincludeqPCs,qworkstations,qWebqservers,qmailq
servers,qPDAs,qInternet-connectedqgameqconsoles,qetc.

2. FromqWikipedia:qDiplomaticqprotocolqisqcommonlyqdescribedqasqaqsetqofqinternation
alqcourtesyqrules.qTheseqwell-establishedqandqtime-
honoredqrulesqhaveqmadeqitqeasierqforqnationsqandqpeopleqtoqliveqandqworkqtogether.
qPartqofqprotocolqhasqalwaysqbeenqtheqacknowledgmentqofqtheqhierarchicalqstandingq
ofqallqpresent.qProtocolqrulesqareqbasedqonqtheqprinciplesqofqcivility.
3. Standardsqareqimportantqforqprotocolsqsoqthatqpeopleqcanqcreateqnetworkingqsystemsq
andqproductsqthatqinteroperate.

4. 1.qDial-
upqmodemqoverqtelephoneqline:qhome;q2.qDSLqoverqtelephoneqline:qhomeqorqsmallqo
ffice;q3.qCableqtoqHFC:qhome;q4.q100qMbpsqswitchedqEthernet:qenterprise;q5.qWifiq(
802.11):q homeqandqenterprise:q6.q3Gqandq4G:qwide-areaqwireless.

5. HFCqbandwidthqisqsharedqamongqthequsers.qOnqtheqdownstreamqchannel,qallqpackets
qemanateqfromqaqsingleqsource,qnamely,qtheqheadqend.qThus,qthereqareqnoqcollisionsq
inqtheqdownstreamqchannel.

6. InqmostqAmericanqcities,qtheqcurrentqpossibilitiesqinclude:qdial-
up;qDSL;qcableqmodem;qfiber-to-the-home.

7. EthernetqLANsqhaveqtransmissionqratesqofq10qMbps,q100qMbps,q1qGbpsqandq10qGbps.

8. Today,qEthernetqmostqcommonlyqrunsqoverqtwisted-
pairqcopperqwire.qItqalsoqcanqrunqoverqfibersqopticqlinks.

9. Dialqupqmodems:qupqtoq56qKbps,qbandwidthqisqdedicated;qADSL:qupqtoq24qMbpsqdo
wnstreamqandq2.5qMbpsqupstream,qbandwidthqisqdedicated;qHFC,qratesqupqtoq42.8q
Mbpsqandqupstreamqratesqofqupqtoq30.7qMbps,qbandwidthqisqshared.qFTTH:q2-
10Mbpsqupload;q10-20qMbpsqdownload;qbandwidthqisqnotqshared.

10. ThereqareqtwoqpopularqwirelessqInternetqaccessqtechnologiesqtoday:

a) Wifiq(802.11)qInqaqwirelessqLAN,qwirelessqusersqtransmit/receiveqpacketsqto/fromqan
qbaseqstationq (i.e.,qwirelessqaccessqpoint)qwithinqaqradiusqofqfewqtensqofqmeters.qThe
qbaseqstationqisqtypicallyqconnectedqtoqtheqwiredqInternetqandqthusqservesqtoqconnect
qwirelessqusersqtoqtheqwiredqnetwork.
b) 3Gqandq4Gqwide-
areaqwirelessqaccessqnetworks.qInq theseq systems,q packetsq areqtransmittedqoverqtheqs
ameqwirelessqinfrastructurequsedqforqcellularqtelephony,qwithqthe



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, baseq stationq thusq beingq managedq byq aq telecommunicationsq provider.q Thisq provid
esqwirelessqaccessqtoqusersqwithinqaq radiusqofqtensqofqkilometersqofqtheqbaseqstation
.

11. Atqtimeqt0q theqsendingqhostqbeginsqtoqtransmit.qAtqtimeqt1q=qL/R1,qtheqsendingqhostq
completesqtransmissionqandqtheqentireqpacketqisqreceivedqatqtheqrouterq(noqpropagati
onqdelay).qBecauseqtheqrouterqhasqtheqentireqpacketqatqtimeqt1,qitqcanqbeginqtoqtransm
itqtheqpacketqtoqtheqreceivingqhostqatqtimeqt1.qAtqtimeqt2q =qt1q +qL/R2,qtheqrouterqco
mpletesqtransmissionqandqtheqentireqpacketqisqreceivedqatqtheqreceivingqhostq(again,q
noqpropagationqdelay).qThus,qtheqend-to-endqdelayqisqL/R1q +qL/R2.

12. Aqcircuit-switchedqnetworkqcanqguaranteeqaqcertainqamountqofqend-to-
endqbandwidthqforqtheqdurationqofqaqcall.qMostqpacket-
switchedqnetworksqtodayq(includingqtheqInternet)qcannotqmakeqanyqend-to-
endqguaranteesqforqbandwidth.qFDMqrequiresqsophisticatedqanalogqhardwareqtoqshift
qsignalqintoqappropriateqfrequencyqbands.


13. a)q 2qusersqcanqbeqsupportedqbecauseqeachquserqrequiresqhalfqofqtheqlinkqbandwidth.

b) Sinceqeachquserqrequiresq1Mbpsqwhenqtransmitting,qifqtwoqorqfewerqusersqtransm
itqsimultaneously,qaqmaximumqofq2Mbpsqwillqbeqrequired.qSinceqtheqavailableqb
andwidthqofqtheqsharedqlinkqisq2Mbps,qthereqwillqbeqnoqqueuingqdelayqbeforeqthe
qlink.qWhereas,qifqthreequsersq transmitq simultaneously,q theq bandwidthq required
qwillqbeq3Mbpsqwhichqisqmoreqthanqtheqavailableqbandwidthqofqtheqsharedqlink.q
Inqthisqcase,qthereqwillqbeqqueuingqdelayqbeforeqtheqlink.

c) Probabilityqthatqaqgivenquserqisqtransmittingq=q0
.2
3q q 3 3−3
d) Probabilityqthatqallqthreequsersqareqtransmittingqsimultaneouslyq=q q (1q−qp)
qp 3




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