Network Test 2

Front 1

At the data link level Hosts and routers are ____ and networks in between them are _____

Back 1

nodes, Links

Front 2

What are the two types links

Back 2

Point-to-point with dedicated medium

broadcast link with a shared medium

Front 3

What does the data link layer do

Back 3

-Receives services from the physical layer

-provides services to the network layer

-Handles node-to-node communication across individual links

Front 4

Frames(or called data link packets).....

-The source node will ______

-The destination node will______

-All in-between nodes most _______ then ________

Back 4

encapsulate

decapsulate

decapsulate

re-encapsulate

Front 5

Framing

Back 5

The packaging of network datagrams into data link frames

Front 6

Flow Control

Back 6

At a minimum, dealing with the case of an incoming packet when receive buffer is full

Front 7

Error Control

Back 7

Detecting, discarding, and possibly requesting the re-transmission of corrupted frames

Front 8

Why link layer Addresses?

▪Recallthat the TCP/IP model of networking is a layered model

▪Fora network packet to reach its destination, it has to proceed through a numberof actual “hops”

▪Each hop by definition is a data link communication

Back 8

▪Eachnode to have its own link layer address▪Linklayer addresses can also be called physicaladdresses,linkaddresses,orMACaddresses▪Thesource and destination link addresses change with each hop; the IP addressesnever do

Front 9

Unicast addresses

Back 9

Point to a single host

Front 10

Multicast addresses

Back 10

Point to multiple hosts

Front 11

Broadcast Address

Back 11

Point to all hosts

Front 12

IPv4

Bits?

Layer?

function?

Back 12

-32-bit IP address

-Network-Layer address

-Used to get datagram to destination IP subnet

Front 13

IPv6

Bits?

Back 13

128 bit IP address

Front 14

Mac address

Function?

bits?

Who allocates addresses?

Back 14

-Get frame from one interface to another physically-connected interface(same network)

-48 bit address

-IEEE

Front 15

Does each adapter have unique mac address

Back 15

Yes

Front 16

Hubs

Layer?

Bits coming in on link go out _____ other links at same time.

Frame buffering?

____ detect collisions

Back 16

physical layer

all

yes

host NICs

Front 17

Switch

Layer?

Are host aware of presence of switch?

Do switches need to be configured

Back 17

-Link-layer device: Smarter than hubs, Take active roll

-No, switch is transparent

-No, switches are plug-and-play, self-learning

Front 18

Switch: allows multiple simultaneous transmissions

Not question just info.

Back 18

▪hostshave dedicated, direct connection to switch

▪switchesbuffer packets

▪eachlink is its own collision domain

▪switching:A-to-A’ and B-to-B’ simultaneously, without collisions

▪notpossible with dumb hub

Front 19

▪howdoes switch know that A’ reachable via interface 4, B’ reachable via interface5?

Back 19

eachswitch has a switchtable, :

eachentry is a tuple (MAC address of host, interface toreach host, time stamp)

Front 20

Where does switch record sender/location pair

Back 20

The switch table

Front 21

sending from A to F - how does S1 know to forward frame destinedto F via S4 and S2?

Back 21

self learning! (works exactly the same asin single-switch case!)

Front 22

Switch vs Router

Back 22

-Both store and forward devices

-routers" network layer device

-switchers are link layer device

-routers maintain routing tables, implement routing algorithms

-switches maintain switch tables, implement filtering, learning algorithms.

Front 23

hubs

traffic isolation?

plug and play?

optimal routing?

Back 23

no

yes

no

Front 24

routers

traffic isolation?

plug and play?

optimal routing?

Back 24

yes

no

yes

Front 25

switches

traffic isolation?

plug and play?

optimal routing?

Back 25

yes

yes

no

Front 26

Arethe link layer addresses changed at each hop?

Back 26

yes

Front 27

Doeseach switch port have a unique MAC address?

Back 27

no

Front 28

Whydo routers need IP addresses?

Back 28

Routershave IP addresses because they sometimes need to send IP packets

Front 29

Address Resolution protocol's Job?

Back 29

-To take an IP address and turn it into a data link address

-It does this by broadcasting a packet over the local network asking for the owner of the ip address to respond

Front 30

ARP packet identify:

Back 30

▪Thehardwaretype(i.e., which link layer protocol)

▪Theprotocoltype(i.e., which network protocol)▪Thesize of each address

▪Notethat each address is not necessarily 32 bits, or even a multiplethereof

▪Whetherthe packet is a request or a reply

▪Theaddresses involved

Front 31

single-bit error

Back 31

only one bit in the data unit was corrupted, or has changed

Front 32

burst error

Back 32

Any number of bits have changed

Front 33

What is more difficult correction or detection

Back 33

Correction

Front 34

What is central concept in both detecting and correcting errors

Back 34

Redundancy

▪Sendextra bits with the data

▪Usethe extra bits to detect and/or correct corruption

Front 35

Dataword

Back 35

smallest black of data in block coding

Front 36

Codeword

Back 36

encoded dataword

Front 37

When we reveive and invalid codeword we ______ it

Back 37

discard

Front 38

Parity bit

Back 38

bit added to a string of binary code that indicates whether the number of 1-bits in the string is even or odd

Front 39

Hamming distance(x,y)

Back 39

-Number of difference in corresponding bits between same-sized word x and y

-equal to the number of corrupted bits

Front 40

Minimum hamming distance

Back 40

smallest hamming between all valid codewords

Front 41

Frames can be ____ or ___ in size

Back 41

fixed

variable

Front 42

Framing

Back 42

packages a single network level datagram into a set of one or more link level frames

Front 43

Frames

Back 43

discrete units of bits that are addressed from a sender to a destination

Front 44

Are large datagrams typically broken into many frames

Back 44

yes

Front 45

Character oriented framing

Back 45

-in this mode of framing, data are always in chunks of characters(or 8 bits)

-flag is used to indicate where the frame begins and ends

Front 46

escape character

Back 46

indicates that next character is not a flog

Front 47

in a connectionless protocol, every frame is ______

Back 47

independent

▪Thevast majority of LANs are like this

Front 48

in connection-oriented protocol, there is a _______

Back 48

logical connection between two nodes

▪Thisincludes at the very least a connection state, and may even include packetordering▪Somenetworks that aren’t LANs use this

Front 49

What does point to point protocol(ppp) define or provide

Back 49

▪Theframe format

▪Link-establishmentnegotiation

▪Dataexchange

▪Authentication

▪Networkaddress configuration

Front 50

What does point to point protocol(ppp) not define or provide

Back 50

▪Flowcontrol

▪Sequencing

▪Errorcontrol beyond detect-and-discard

Front 51

PPP's frames are _____ oriented

Back 51

character

Front 52

Link control protocol

Back 52

Used to establish, maintain, configure and terminate links

Front 53

Communication at the data link layer is ___.

Back 53

node-to-node

Front 54

Communication at the network layer is _____.

Back 54

Host to Host

Front 55

T/F: Address Resolution Protocol's ARP job is to take a data link address and turn it into an IP address

Back 55

false

Front 56

T/F: We need to always keep the arp program running on a host or router

Back 56

true

Front 57

An ARP request is normally

Back 57

Broadcast

Front 58

An ARP reply is normally

Back 58

Unicast

Front 59

Packet at the data-link layer is normally called

Back 59

Frame

Front 60

Which error detection method uses one's complement arithmetic

Back 60

Checksum

Front 61

in cyclic redundancy checking what forms the check bits are

Back 61

the remainder

Front 62

at the CRC checker, _______ means that the data word is damaged.

Back 62

a nonzero remainder

Front 63

IN CRC, if the remainder is only three bits, the divisor should be _____ bits

Back 63

4

Front 64

To detect five errors, the hamming distance between each pair of codewords should be at least ___

Back 64

6

Front 65

To correct five errors, the hammering distance between each pair of codewords should be at least_____

Back 65

11

Front 66

If 3 bits are used for the frame sequence number in Go-back-n ARQ, the size of the sender's window size can have the following value

Back 66

5 frames

Front 67

Consider a Stop-and-wait ARQ protocol that uses a time-out period of 18 ms (milliseconds). The round trip times between the sender and receiver is 10 ms. The transmission time of a frame is 2ms. The value of the utilization of this protocol in an error free channel is____

Back 67

2/12

Front 68

The timeout counter in the go-back-n ARQ protocol is used to ______

Back 68

initiate frame retransmission

Front 69

In go-Back-n, the values of Sf = 3 and Sn = 7, after receiving a packet with ackNo = 6, the value of Sf is ____

Back 69

6

Front 70

T/F: ARQ protocols can be used only on the data link layer

Back 70

false

Front 71

In the 1-persistent approach of CSMA, When a station finds an idle line it ______.

Back 71

Sends immediately

Front 72

_______ is(are) a channelization protocal

FDMA

TDMA

CDMA

Back 72

None

Front 73

_____ is a local address, Its jurisdiction is over a local network

Back 73

Link-layer address

Front 74

If the sender is a host and wants to send a packet to another host on the same network, the logical address that must be mapped to a physical address is ______.

Back 74

The Destination IP address in the datagram header

Front 75

If the sender is a host and wants to send a packet to another host on another network, the logical address that must be mapped to a physical address is ______.

Back 75

the IP address of the router found in the routing table

Front 76

The sender is a router that has received a datagram destined for a host on another network. The logical address that must be mapped to a physical address is ______.

Back 76

The IP address of the router found in the routing table

Front 77

The sender is a router that has received a datagram destined for a host in the same network. The logical address that must be mapped to a physical address is ______.

Back 77

the destination IP address in the datagram header

Front 78

In a _______ link, the link is not shared between devies

Back 78

Point to point

Front 79

In a _____ link, the link is shared between many devices

Back 79

broadcast

Front 80

Data-link layer of broadcast link had _____ sublayers

Back 80

2

Front 81

Data-link layer of point to point link had ______ sublayers

Back 81

1

Front 82

Media access control can be present only in a _____ link

Back 82

multicast

Front 83

Which of the following best describes a single-bit error?

A)A single bit is inverted

B)A single bit per transmission is inverted

C)A single bit per data unit is inverted

D)All of the choices are correct

Back 83

A single bit per data unit is inverted

Front 84

Which error detection method uses one's complement arithmetic?

Back 84

Checksum

Front 85

Which error detection method consists of just one redundant bit per data unit?

Back 85

Simple parity check

Front 86

Which error detection method involves polynomials

Back 86

CRC

Front 87

If the ASCII character g is sent and the character d is received, what type of error is this

Back 87

burst error

Front 88

If the ascii character H is sent and the character and the character L is received, what type of error is this

Back 88

single bit

Front 89

In Cyclic redundancy checking, what forms the check bits?

Back 89

the remainder

Front 90

In CRC, if the dataword is 111111, the divisor 1010, and the remainder 110, what is the codeword at the receiver?

Back 90

dataword plus remainder = 111111110

Front 91

At the CRC generator, _______ is (are) added to the dataword after the division process to create the codeword.

Back 91

the remainder

Front 92

The sum of the checksum and data at the receiver is _______ if no error is detected.

Back 92

-0

Front 93

In CRC, the quotient at the sender _____

Back 93

is discarded

Front 94

At the CRC checker, _____ means that the dataword is damaged

Back 94

a nonzero remainder

Front 95

A codeword of 10 bits has only four 0s, how many terms are in the polynomial representation of this code?

Back 95

6

Front 96

In CRC, if the remainder is only three bits, the divisor should be __________ bits.

Back 96

4

Front 97

A checksum can _________ errors.

A)only detect

B)only correct

C)both detect and correct

D)None of the choices are correct

Back 97

both detect and correct

Front 98

HDLC is an acronym for

Back 98

High Level Data Link Control

Front 99

The shortest frame in HDLC protocol is usually the _____ Frame

Back 99

supervisory

Front 100

The address field of the frame in HDLC protocol contains the address of the _____ station

Back 100

secondary

Front 101

The HDLC _____ field defines the beginning and end of a frame

Back 101

flag

Front 102

what is present in all HDLC control fields

Back 102

P/f bit

Front 103

According to the PPP transition-phase-diagram, options are negotiated in the _____ state

Back 103

establishing

Front 104

According to the PPP transition phase diagram, verification of user identification occurs in the _____ state

Back 104

authenticating

Front 105

In the PPP frame, the _____ field defines the contents of the data field

Back 105

protocol

Front 106

in the PPP frame, the ____ field is similar to that of the U-frame in HDLC

Back 106

control

Front 107

In the PPP frame, the ____ field has a vallue of 11111111 to indicate the broadcast address of HDLC

Back 107

address

Front 108

In PPP, what is the purpose of LCP packets

A)Configuration

B)Termination

C)Option negotiation

D)All of the choices are correct

Back 108

All of above

Front 109

In PPP frame, the ____ field is for error control

Back 109

FCS

Front 110

For CHAP authentication, the user takes the system’s _______ and its own _______ to create a result that is then sent to the system.

Back 110

challenge value; password

Front 111

In byte stuffing, we need sometimes to add a (an) _____ in the payload

Back 111

ESC byte

Front 112

In bit stuffing, we sometimes need to add an extra ___________ bit in the payload.

Back 112

0's

Front 113

HDLC is a _____ oriented protocol

Back 113

byte

Front 114

PPP is a ______ oriented protocol

Back 114

byte

Front 115

In PPP, the address field defines ____ of the packets.

A)the sender

B)the receiver

C)either the sender or the receiver

D)None of the choices are correct

Back 115

none are correct

Front 116

int PPP, the ______ field defines the type of payload encapsulated in the frame

Back 116

Protocol

Front 117

In PPP, the Chap protocol uses _____ steps to authenticate the parties in communication

Back 117

three

Front 118

In the _______ random-access method collision is avoided.

Back 118

CSMA/CA

Front 119

In the 1-persistent approach, when a station finds an idle line, it _______.

Back 119

sends immediaately

Front 120

_______ requires one primary station and one or more secondary stations.

Back 120

Polling

Front 121

In the p-persistent approach, when a station finds an idle line, it _______.

Back 121

sends with probability p

Front 122

The 1-persistent approach can be considered a special case of the p-persistent approach with p equal to _______.

Back 122

1.0

Front 123

In the reservation access method, if there are 10 stations on a network, then there are _______ reservation minislots in the reservation frame.

Back 123

10

Front 124

_______ is a controlled-access protocol.

Back 124

Reservation

Front 125

_______ is (are) a channelization protocol.

A)FDMA

B)TDMA

C)CDMA

D)All the choices are correct

Back 125

All of the above

Front 126

In the _______ random-access method, stations do not sense the medium.

Back 126

ALOHA

Front 127

Which of the following is an example of a random-access protocol?

A)Polling

B)FDMA

C)Token passing

D)None of the choices are correct

Back 127

None

Front 128

Which of the following is an example of a controlled-access protocol?

Back 128

Token Passing

Front 129

The vulnerable time for a pure ALOHA is __________ the one for slotted ALOHA.

Back 129

greater than

Front 130

The vulnerable time for CSMA is ___________.

Back 130

2 x Tp

Front 131

We need RTS and CTS packets in ____________ protocol.

Back 131

CDMA/CA

Front 132

TIn FDMA, we use different ___________ to achieve channelization.

Back 132

frequency ranges

Front 133

In CDMA, we use different ___________ to achieve channelization.

Back 133

codes

Front 134

In TDMA, we use different ___________ to achieve channelization.

Back 134

time slots

Front 135

Walsh tables are used in _________________.

Back 135

TDMA

Front 136

A VLAN is a locol area network configured by _______

Back 136

Software

Front 137

A Repeater is a connected device that operates in the ___ layer

Back 137

physical

Front 138

a link-layer switch is a connecting device that operates in the ______ layer

Back 138

physical and data-link

Front 139

a router is a connecting device that operates in the ___ layer

Back 139

physical, data-link, and network

Front 140

A _________ has no filtering capability.

Back 140

repeater

Front 141

A three-layer switch is a __________.

Back 141

router

Front 142

A router filters packets based on the __________ destination addresses.

Back 142

Network layer

Front 143

-A link-layer switch filters packets based on the __________ destination addresses.

Back 143

data-link

Front 144

Looping problems in a set of swtiches can be eliminated using ___________ algorithm.

Back 144

spanning-tree

Front 145

Membership in a VLAN can be based on ________.

A)interface numbers

B)MAC addresses

C)IP addresses

D)All of the choices are correct

Back 145

All of the above