export_final Flashcards

1
Q

TCP implements network fairness directly.

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

TCP has a congestion control mechanism.

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

TCP implements network fairness indirectly.

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some possible consequences of network-core congestion? (Check all that apply)

A

Delayed packets Network collapse Dropped Packets Out-of-order packet arrival Increased network congestion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Given a 4 Gbps link with TCP applications A, B, and C. Application A has 29 TCP connections to a remote web server Application B has 2 TCP connection to a mail server Application C has 14 TCP connections to a remote web server. According to TCP “fairness”, during times when all connections are transmitting, how much bandwidth should Application C have? (Give answer in Mbps, rounded to one decimal place, without units. So for an answer of 1234,567,890 bps you would enter “1234.6” without the quotes.)

A

1244.4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

For the following binary IP address, give the dotted-decimal representation: 11000000 10101000 00001011 00010100

A

192.168.11.20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

For the following dotted-decimal IP address, give the binary representation: 10.108.112.240

A

00001010 01101100 01110000 11110000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

For the following binary IP address, give the dotted-decimal representation: 10011000 11101110 10011101 11000011

A

152.238.157.195

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A network with a connectionless network layer is called a datagram network .

A

datagram network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In a subnet, the reserved addresses are the __________ (with a lowest subnet IP address) and the ____________ (with a highest subnet IP address).

A

subnet address, broadcast address

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When a host in a network needs to obtain a valid IP address for itself, it broadcasts a “discover” message that can be handled by a Dynamic Host Configuration Protocol (DHCP) server, which will “offer” an IP address within the correct domain.

A

Dynamic Host Configuration Protocol (DHCP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The Internet Protocol (IP) implements flow control.

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The process of moving a datagram from a router’s input port to output port is handled by the switching fabric .

A

switching fabric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In addition to a “default” entry, routing tables in an internet store…

A

the “first hop” in a path to each of the networks known to the router

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In a datagram network, the responsibilities of the network layer include: (check all that apply).

A

host-to-host communication packet forwarding packet routing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Given a router with 5 input ports and 5 output ports. If the switching fabric is 5 times as fast as the input/output line speed, queueing can occur at an output port.

A

can

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where do network-layer protocols run?

A

PCs Mobile devices Laptops Routers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The Internet Protocol (IP) header may be 28 bytes long.

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What can cause packet queueing at a router’s output port?

A

Multiple data flows requiring the same outbound link. Slow outbound link transmission rate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

The Internet Protocol (IP) implements data reliability services

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The network layer manages communications from host to host .

A

host to host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The Internet Protocol (IP) header may be 21 bytes long.

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

For the IPv4 CIDR address 153.10.22.56 /22 What is the… Netmask: Network Address: Host Mask: 0.0.3.255 Broadcast Address: Number of possible hosts: 1022 Host Number:

A

Answer 1: Correct! 255.255.252.0 Answer 2: Correct! 153.10.20.0 Answer 3: Correct! 0.0.3.255 Answer 4: Correct! 153.10.23.255 Answer 5: Correct! 1022 Answer 6: Correct! 568

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are some causes of network congestion? (Check all that apply)

A

Typical Internet Usage. Correct! Parallel TCP Connections. Correct! High utilization. Correct! Dropped TCP Packets. Correct! Reliable Data Transfer schemes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

A host starts a TCP transmission with an EstimatedRTT of 10.2ms (from the “handshake”). The host then sends 3 packets and records the RTT for each: SampleRTT1 = 39.7 ms SampleRTT2 = 37.8 ms SampleRTT3 = 19.4 ms (NOTE: SampleRTT1 is the “oldest”; SampleRTT3 is the most recent.) Using an exponential weighted moving average with a weight of 0.4 given to the most recent sample, what is the EstimatedRTT for packet #4? Give answer in miliseconds, rounded to one decimal place, without units, so for an answer of 0.01146 seconds, you would enter “11.5” without the quotes.

A

24.8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

For the following binary IP address, give the dotted-decimal representation: 11011110 01110011 01100110 01100110

A

222.115.102.102

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

In a datagram network, the responsibilities of the network layer include: (check all that apply).

A

Correct Answer host-to-host communication Correct Answer packet routing Correct Answer packet forwarding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

In host-inferred congestion control, congestion is detected based on delayed and/or dropped packets.

A

host inferred

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

UDP uses an additive-increase multiplicative-decrease (AIMD) system to manage flows.

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Select the appropriate new CongWin sizes for the following TCP Reno congestion scenario. Assume ssthresh is initially set to 8 MSS: Connection Established with new server host. CongWin = ACK(s) received from first segment set. CongWin = ACK(s) received from next segment set. CongWin = 2 MSS ACK(s) received from next segment set. CongWin = ACK(s) received from next segment set. CongWin = ACK(s) received from next segment set. CongWin = Triple Duplicate ACK occurs. CongWin = , ssthresh = 4 MSS ACK(s) received from next segment set. CongWin =

A

Connection Established with new server host. CongWin = 1MSS ACK(s) received from first segment set. CongWin = 2MSS ACK(s) received from next segment set. CongWin = 4 MSS ACK(s) received from next segment set. CongWin = 8MSS ACK(s) received from next segment set. CongWin = 9MSS ACK(s) received from next segment set. CongWin = 10MSS Triple Duplicate ACK occurs. CongWin = 8MSS , ssthresh = 5 MSS ACK(s) received from next segment set. CongWin = 9MSS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Given a nodal delay of 64.7ms when there is no traffic on the network (i.e. usage = 0%), what is the effective delay when network usage = 94.6% ? (Give answer is miliseconds, rounded to one decimal place, without units. So for an answer of 0.10423 seconds you would enter “104.2” without the quotes). You Answered

A

1198.1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Which of the following are benefits of a virtual circuit network? (Check all that apply)

A

Correct! Guaranteed timing. Correct! Guaranteed bandwidth. Correct! Connection states are preserved.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Which of the following are benefits of a datagram network? (Check all that apply)

A

Faster delivery. Less overhead than a VC network.

34
Q

A network with a connection-oriented network layer is called a

A

virtual circuit network

35
Q

The path MTU is the smallest MTU on a path from sender to receiver

A

true

36
Q

The “ping” application (on Windows) uses ICMP echo request/reply.

A

true

37
Q

Network address translation is strictly a Layer-3 protocol.

A

false

38
Q

ICMP messages are carried within the payload of IP datagrams.

A

true

39
Q

It is the responsibility of a routing algorithm to correlate MAC addresses with IP addresses.

A

false

40
Q

For a TCP/IP datagram leaving a home network through a NAPT device, which of the following header fields (IP and/or TCP) are altered? (Check all that apply)

A

source port Source ip address Header checksum

41
Q

If an IP datagram is fragmented into 1000-byte fragments, and later encounters a link with an 800-byte MTU, it is dropped.

A

false

42
Q

The “Identification” header field is unchanged by IP datagram fragmentation.

A

true

43
Q

The IP header is encapsulated in IP datagram fragments.

A

false

44
Q

For the IPv4 CIDR address 146.10.150.116 /24 What is the… Netmask: Network Address: Host Mask: Broadcast Address: Number of possible hosts: 254 Host Number:

A

Netmask: 255.255.255.0 Network Address: 146.10.150.0 Host Mask: 0.0.0.255 Broadcast Address: 146.10.150.255 Number of possible hosts: 254 Host Number: 116

45
Q

A private network uses a NAPT device at public IP address 207.96.121.8 The computers in the network use addresses of the form 10.0.0.x/22. Suppose that computer inside the NATed network sends a request with Source address: 10.0.2.5 Source port: 750 Destination address: 128.193.4.20 Destination port: 60 The next available port number on the NAPT device is 12345. PART 1: What source and destination information do the request packet headers contain when the request is sent out by the sending host? Source address: Source port : Destination address: Destination port : PART 2: What source and destination information do the request packet headers contain when the request is sent out by the NAT box? Source address: Source port : Destination address: Destination port : PART 3: What source and destination information do the response packet headers contain when the response is received by the NAT box? Source address: Source port : Destination address: Destination port : PART 4: What source and destination information do the response packet headers contain when the response is received by the original sending host? Source address: Source port : Destination address: Destination port :

A

PART 1: What source and destination information do the request packet headers contain when the request is sent out by the sending host? Source address: 10.0.2.5 Source port : 750 Destination address: 128.193.4.20 Destination port : 60 PART 2: What source and destination information do the request packet headers contain when the request is sent out by the NAT box? Source address: 207.96.121.8 Source port : 12345 Destination address: 128.193.4.20 Destination port : 60 PART 3: What source and destination information do the response packet headers contain when the response is received by the NAT box? Source address: 128.193.4.20 Source port : 60 Destination address: 207.96.121.8 Destination port : 12345 PART 4: What source and destination information do the response packet headers contain when the response is received by the original sending host? Source address: 128.193.4.20 Source port : 60 Destination address: 10.0.2.5 Destination port : 750

46
Q

Suppose that a 2500-byte datagram (identification #23) must transit a network which has a 740-byte MTU. Assume the minimum IP and TCP header sizes, i.e., the IP header is 20 bytes and the TCP header is 20 bytes. How many fragments are created? fragments How many bytes of application data are carried in the first fragment? bytes How many bytes of application data are carried in the second fragment? 720 bytes How many bytes of application data are carried in the last fragment? bytes What is the identification number of the second fragment? # What is the fragment offset in the last fragment?

A

How many fragments are created? 4 fragments How many bytes of application data are carried in the first fragment? 700 bytes How many bytes of application data are carried in the second fragment? 720 bytes How many bytes of application data are carried in the last fragment? 320 bytes What is the identification number of the second fragment? # 23 What is the fragment offset in the last fragment? 270

47
Q

NAPT devices translate IP address and port numbers.

A

true

48
Q

If hosting a server inside a NATed network, how do clients outside the NAPT router connect to the server? (Check all that apply)

A

Correct! By using the NAPT devices IP address, and a port number pre-configured to correspond to the server. Correct! Using Universal Plug and Play (UPnP) Correct! Through a connection relay service

49
Q

The IP header is encapsulated in IP datagram fragments.

A

false

50
Q

The transport-layer header is encapsulated in the first fragmented IP datagram.

A

true

51
Q

The “time to live” field in a modern IPv4 datagram header specifies…

A

number of hops before datagram is dropped

52
Q

Network address translation alters IP to add new IP addresses.

A

False It doesn’t add IP addresses, it just re-uses them.

53
Q

Re-assembly of fragmented IP datagrams is handled by…

A

the destination host.

54
Q

The IPv6 address size is 120 bits.

A

false

55
Q

In IPv6, there is no datagram fragmentation performed in the network core..

A

true

56
Q

Select all features explicit in IPv6 which are not explicitly available in IPv4.

A

Correct! 128-bit Addresses Correct! Payload Length Correct! Flow labeling Correct! Extension Headers

57
Q

The IPv6 address size is 128 bits.

A

true

58
Q

In IPv6, datagram fragmentation is handled at the network edge .

A

handled at the network edge

59
Q

1234:aac:a03::abcd is a valid preferred-format IPv6 address.

A

true

60
Q

1234::a03::abcd is a valid preferred-format IPv6 address.

A

false

61
Q

::ffff:ffff:fffff is a valid preferred-format IPv6 host address.

A

false It doesn’t add IP addresses, it just re-uses them.

62
Q

Ethernet provides… error detection via CRC check

A

true

63
Q

t is fairly easy to detect collisions in wired networks.

A

true

64
Q

A switch is a network-layer device.

A

false

65
Q

For an machine using 2-dimensional even parity for error detection/correction, and the following received bytes, where is the error? If there is no error, select “No Error” for both boxes. Byte # Code Parity 1 1000 011 1 2 1000 110 0 3 1001 101 0 4 1100 011 0 5 1101 000 1 6 1100 110 0 7 1010 100 1 Parity 1111 001 1

A

Byte # 2 Bit # 4

66
Q

In a CSMA/CD system, when a collision is detected, …

A

the sender will cut off transmission and wait some time before retransmitting.

67
Q

The data-link layer provides logical communications between adjacent node and adjacent node .

A

true

68
Q

Given the following received byte on an odd-parity machine, there is definitely at least one error. 01001101

A

true

69
Q

When sending a message to all devices on a link, you would send it to the broadcast MAC address: 00-00-00-00-00-00

A

false

70
Q

Star Ethernet uses the same multiple access control as Bus Ethernet.

A

false

71
Q

Which are functions of the Ethernet preamble? (Check all that apply)

A

circuit wake-up Start signal Clock sync

72
Q

A MAC address is permanent and unique.

A

false

73
Q

The method by which a MAC protocol coordinates access to a broadcast medium to prevent and/or reduce collisions is most commonly called ________

A

multiple access

74
Q

A link-layer link between only two adjacent nodes is called a/an point to point link.

A

true

75
Q

A link-layer link between more than two adjacent nodes is called a/an broadcast link.

A

true

76
Q

It is fairly easy to detect collisions in wireless networks.

A

false It doesn’t add IP addresses, it just re-uses them.

77
Q

Ethernet uses a RTS/CTS contention-free period.

A

false

78
Q

In an Ethernet network, after 8 collisions, the range of wait times will be …

A

[0, 1, … 255] * 512 bit times

79
Q

When a mobile unit moves from a home or foreign agent to another (foreign) agent, the new agent must assign…. (Check all that apply)

A

a new “care-of” address to the mobile unit

80
Q

In indirect routing, after the initial contact with the home network, the correspondent sends packets to

A

The permanent address

81
Q

Which of the following are used in a wireless network such as 802.11n?

A

Correct! Exponential back-off/retry for collision resolution Correct! Carrier Sense Multiple Access Correct Answer Collision Avoidance Correct! Reservation system with Request to Send (RTS) and Clear to Send (CTS)

82
Q

The default multiple access scheme of 802.11g is RTS/CTS

A

false