计算机网络教程自顶向下方法选择题 Chapt 4 Network L.docx
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计算机网络教程自顶向下方法选择题Chapt4NetworkL
Chapter4NetworkLayer
1.
Packetizingatthenetworklayerinvolves
A）Encapsulatingthepayloadatthesource
B）Addsaheaderthatcontainsthesourceanddestinationinformation
C）Decapsulatingthepayloadatthedestination
D）Allofthechoicesarecorrect
2.
Routersinthepatharenotallowedto___________________________.
A）fragmentthepackettheyreceive
B）decapsulatethepacket
C）changesourceordestinationaddress
D）Allofthechoicesarecorrect
3.
ThenetworklayerintheInternetprovides_________________.
A）comprehensiveerrorandflowcontrol.
B）limitederrorcontrol,butnoflowcontrol.
C）comprehensiveerrorcontrolbutlimitedflowcontrol.
D）Allofthechoicesarecorrect
4.
Inavirtual-circuitapproach,theforwardingdecisionisbasedonthevalueofthe_____________fieldinthepacketheader.
A）sourceaddress
B）destinationaddress
C）label
D）Noneofthechoicesarecorrect
5.
Inadatagramapproach,theforwardingdecisionisbasedonthevalueofthe_____________fieldinthepacketheader.
A）sourceaddress
B）destinationaddress
C）label
D）Noneofthechoicesarecorrect
6.
Theperformanceofanetworkcanbemeasuredintermsof________.
A）delay
B）throughput
C）packetloss
D）allofthechoicesarecorrect
7.
Transmissiondelay（time）istheratioof______________________.
A）transmissionratetopacketlength
B）transmissionratetodistance
C）packetlengthtotransmissionrate
D）processingtimetotransmissionrate
8.
Propagationdelay（time）istheratioof______________________.
A）transmissionratetopropagationspeed
B）propagationspeedtodistance
C）packetlengthtopropagationspeed
D）distancetopropagationspeed
9.
Whentheloadinthenetworkreachesthenetworkcapacity,thepacketdelay___________andthenetworkthroughputreaches______________.
A）increasessharply;itsminimum
B）increasessharply;itsmaximum
C）decreasessharply;itsminimum
D）decreasessharply;itsmaximum
10.
Inopen-loopcongestioncontrol,policiesareapplied____________________.
A）topreventcongestionbeforeithappens
B）toalleviatecongestionafterithappens
C）toeitherpreventcongestionbeforeithappensortoalleviatecongestionafterithappens
D）Noneofthechoicesarecorrect
11.
The__________________techniqueisoneoftheopen-loopcongestionpolicy
A）backpressure
B）chokepacket
C）implicitsignaling
D）Noneofthechoicesarecorrect
12.
The__________________techniqueisoneoftheclose-loopcongestionpolicy
A）acknowledgmentpolicy
B）chokepacket
C）discardingpolicy
D）Noneofthechoicesarecorrect
13.
IPisa_________protocol.
A）connection-orientedunreliable
B）connection-orientedreliable
C）connectionlessunreliable
D）connectionlessreliable
14.
AnHLENvalueofdecimal10means_______.
A）thereare10bytesofoptions
B）thereare10bytesintheheader
C）thereare40bytesofoptions
D）thereare40bytesintheheader
15.
Ifthefragmentoffsethasavalueof100,itmeansthat_______.
A）thedatagramhasnotbeenfragmented
B）thedatagramis100bytesinsize
C）thefirstbyteofthedatagramisbyte800
D）Noneofthechoicesarecorrect
16.
Whatisneededtodeterminethenumberofthelastbyteofafragment?
A）offsetnumber
B）totallength
C）bothoffsetnumberandthetotallength
D）Noneofthechoicesarecorrect
17.
TheIPheadersizeis_______byteslong.
A）20to60
B）20
C）60
D）Noneofthechoicesarecorrect
18.
PacketsintheIPlayerarecalled_________.
A）segments
B）datagrams
C）frames
D）Noneofthechoicesarecorrect
19.
Thetotallengthfielddefinesthetotallengthofthedatagram_________.
A）includingtheheader
B）excludingtheheader
C）excludingtheoptionlength
D）Noneofthechoicesarecorrect
20.
Whenadatagramisencapsulatedinaframe,thetotalsizeofthedatagrammustbelessthanthe_______.
A）MUT
B）MAT
C）MTU
D）Noneofthechoicesarecorrect
21.
AnIPv4addressisnormallyrepresentedinbase____indotted-decimalnotation.
A）16
B）256
C）10
D）Noneofthechoicesarecorrect
22.
Inclassfuladdressing,theIPv4addressspaceisdividedinto_______classes.
A）3
B）4
C）5
D）Noneofthechoicesarecorrect
23.
Thenumberofaddressesassignedtoanorganizationinclasslessaddressing_______.
A）canbeanynumber
B）mustbeamultipleof256
C）mustbeapowerof2
D）Noneofthechoicesarecorrect
24.
Thefirstaddressassignedtoanorganizationinclasslessaddressing_______.
A）mustbeevenlydivisiblebythenumberofaddressesintheorganization
B）mustbedivisibleby128
C）mustbelongtooneoftheA,B,orCclasses
D）Noneofthechoicesarecorrect
25.
Insubnetting,thenumberofaddressesineachsubnetmust_______.
A）beapowero
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