NWC203c

A service model specifies a level of performance that can be expected in the transfer of information. A, True B, False

A

ARQ protocols combine error detection, retransmission and sequence numbering to provide reliability A, True B, False

A

Attackers attempt to gain unauthorized access to server. What type of network security threat it imposes? A. Client imposter B. Server imposter C. Man-in-Middle D. None of the above

A

Based on 1.1.1.0/24, the IP address would be: A. Class A B. Class B C. Class C D. Class D

A

Block codes are generated using _____. A, Generator matrix B, Generator polynomial C, Both of the mentioned D, None of the mentioned

A

CSMA/CD is not used in DCF because A, a station is unable to listen to the channel for collisions while transmitting B, physical carrier sense detects the presence of other WLAN users C, in idle state, a station is unable to listen to the channel for collisions D, None of the above

A

Carrier Sense Multiple Access (CSMA) is based on medium called A, Sense before transmit B, Listen before sending C, Listen before talk D, Sense before Collision

A

Consider a three hop network from the source to the destination. Let m be the message transmission time at each hop. Let n be the propagation delay of each hop. Assume there is no queueing delay and processing time at each hop. Based on cut-through switching, what is the total time for three packets to be transmitted to the destination? A. 3m + 3n B. 5m + 3n C. 9m + 9n D. None of the above

A

Corresponding box of Carrier Sense Multiple Access/Collision Detection can be replaced by one of the A, Persistent process B, P-persistent process C, Non-persistent process D, I-persistent process

A

DISCO Corporation has been assigned the Class B network address 165.87.0.0. DISCO needs to divide the network into eight subnets. What subnet mask should be applied to the network to provide the most hosts per subnet? A. 255.255.240.0 B. 255.255.248.0 C. 255.255.192.0 D. 255.255.224.0

A

Framing involves identifying the beginning and end of a block of information within a digital stream A, True B, False

A

Generic Framing Procedure (GFP) allows the implementation of multiple transport modes that may coexist within the same transport channel A, True B, False

A

Given a subnet mask 255.255.255.240, how many hosts the subnet can support? A. 14 B. 30 C. 62 D. None of the above

A

IPv6 allows fragmentation at A. Source only B. Intermediate routers only C. Both source and intermediate routers D. None of the above

A

If a subnet needs to accommodate up to 500 hosts. How many bits for HostID would be sufficient? A. 9 B. 5 C. 8 D. 7

A

In 802.11 protocol, MAC can alternate between Contention Periods (CPs) and Contention-Free Periods (CFPs) A, True B, False

A

In BSD socket API, which type of socket is used to create a TCP socket? A, SOCK_STREAM B, SOCK_RAW C, SOCK_DGRAM D, None of the above

A

In CSMA/CA, An amount of time divided into slots called A, Contention window B, Contention procedure C, Contention energy D, Contention signals

A

In Carrier Sense Multiple Access (CSMA), possibility of collision still exist because of A, Propagation delay B, Collision delay C, Transmit delay D, None of the above

A

In Carrier Sense Multiple Access with collision detection (CSMA-CD), how long will it take a collision to be detected and resolved? A, Round-trip propagation delay B, One propagation delay C, One frame transmission time D, None of the above

A

In IEEE 802.11 MAC for wireless LANs, which of following inter-frame space (IFS) is used to transmit high-priority frames such as ACKs? A, SIFS B, DIFS C, None of the above D, PIFS

A

In Network Address Translation (NAT), which of the following statement is true for a packet with an associated private IP address at the routers in the global internet A. Discarded due to the nature of the packet address B. Redirected to other routers for address confirmation C. Create an exception and then forward the packet to the destination address in the header D. Forwarded to the destination address in the packet header

A

In Reverse Path Forwarding, router receives a packet and extracts the A. Source address B. Protocol address C. IP address D. Standard address

A

In Routing Information Protocol (RIP), the use of max number limited to 15 limits the count-to-infinity problem A. True B. False

A

In Transmission Control Protocol (TCP), When a segment carries a combination of data and control information, it uses a A. Sequence Number B. Source Number C. Slot Number D. Port Number

A

In a software defined network (SDN), which of the architectural layer is responsible for switch configuration and forwarding instruction? A. Middle layer B. Infrastructure layer C. Security layer D. None of the above

A

In a virtual-circuit packet network, routing is determined during connection set-up A. True B. False

A

In an OSPF network, routers in area only knows complete topology inside area and limits the flooding of link-state information to area A. True B. False

A

In congestion warning, the feedback mechanism can be implicit or explicit. Which of the following is an example of implicit feedback A. A time-out due to missing acknowledgement B. The warning bit in ACKs C. Choke packets to the source D. None of the above

A

In digital transmission, long distance digital communications require the use of a generator to recover original data sequence and re-transmits on next segment A. True B, False

A

In link state routing, after the construction of link state packets new routes are computed using A. Dijkstra's algorithm B. Bellman Ford algorithm C. Leaky bucket algorithm D. None of the above

A

In mobile IP, when a home agent wants to send a packet to a mobile host in a foreign network, each IP packet at the home agent will be encapsulated with an outer IP header. What is the destination IP address in the outer IP header? A. Care-of address B. Mobile host's address C. Home agent's address D. None of the above

A

Of the following, which is a basic function of transparent bridge? A. All of the above B. Learns where stations are attached to the LAN C. Prevents loops in the topology D .Forwards frames from one LAN to another

A

One can use repeaters, bridges and routers to interconnect two LANs. Which of the following approaches will make local traffic appear in both LANs? A. Repeater B. Routers C. Bridges D. All of the above

A

PPP is a data link protocol for point-to-point lines in Internet. Its framing is based on which of the following? A, Byte stuffing B, Bit stuffing C, Word stuffing D, None of the above

A

Perform bit de-stuffing for the following sequence: 11101111101111100111110. A, 11101111111111011111 B, 00010000010000011000001 C, 11100111111110011111 D, None of the above

A

Polynomial codes are implemented using shift register circuits A, True B, False

A

Question 1 Perform the bit stuffing procedure for the following binary sequence: 1101111111011111110101. What is the outcome? A, 110111110110111110110101 B, 110111111101111111010100 C, 0010000000100000001010 D, None of the above

A

Question 4 Which of the following is an application layer protocol? A, HTTP B, UDP C, DNS D, TCP

A

Reverse Path Multicasting (RPM) is used to increase A. Efficiency B. Performance C. Accuracy D. Strength

A

TCP SYN flood attack exploits the TCP three-way handshake A. True B. False

A

The internet protocol allows IP fragmentation so that datagrams can be fragmented into pieces small enough to pass over a link with a smaller MTU than the original datagram size A. True B. False

A

The main purpose of access multiplexer is to combine the typically bursty traffic flows from the individual computers into aggregate flows A. True B. False

A

The primary function of Media Access Control is to minimize or eliminate the instance of the collisions to achieve a reasonable utilization of the medium A, True B, False

A

The process of combining multiple outgoing protocol streams at the Transport and Network layers in TCP/IP is called Multiplexing A. True B. False

A

Time-out period is equal to maximum possible propagation delay of A, Round-trip B, Triangle-trip C, Square-trip D, Rectangle-trip

A

To guarantee network performance during the lifetime of admitted flows, open-loop control relies on the following mechanism except: A. Head-of-Line queueing B. Traffic shaping C. Traffic policing D. Admission control

A

What is the primary benefit provided by the Slotted ALOHA compared to ALOHA? A, Higher maximum throughput B, Lower access delay C, Both of the above D, None of the above

A

What is the root problem of Bellman-Ford algorithm for distance vector approach? A. Counting to infinity B. Flooding overhead C. Cannot work in IP D. All of the above

A

Which OSI layer is responsible for determining which route through the network to use? A, Network layer B, Data link layer C, Transport layer D, None of the above

A

Which OSI layer is responsible for providing end-to-end communication with reliable service? A, Transport layer B, Network layer C, Session layer D, Data link layer

A

Which class of IP addresses does CIDR performs aggregation on? A. Class C B. Class D C. Class B D. Class A

A

Which flag bit in TCP header must be set when a TCP client initiates a three-way handshake? A. SYN B. ACK C. RST D. None of the above

A

Which flag bit in TCP header must be set when a TCP entity wants to terminate a connection? A. FIN B. SYN C. RST D. ACK

A

Which of following features are typically true for local area networks? A, All of the above B, Low error rate C, High speed D, Low round-trip delay

A

Which of following is not a primary responsibility of the MAC sublayer in LANs? A, Reliable connection-oriented service B, Channel access C, Protocol data unit addressing D, Fragmentation and reassembly of MAC service data unit

A

Which of following is the implementation of distance vector approach in the IP routing protocol? A. RIP B. OSPF C. BGP D. None of the above

A

Which of following statements is true about how the data link layer and transport layer differ? A, Data link layer is concerned with framing and the transport layer is not B, Data link layer is concerned with flow control and the transport layer is not C, Data link layer is concerned with multiplexing and the transport layer is not D, All of the above

A

Which of following statements most accurately describes the reverse-path broadcasting? A. It assumes that the shortest path from the source to a given router should be the same as the shortest path from the router to the source B. Each link in the network to be symmetric C. Each packet is forwarded by a router exactly once D. All of the above

A

Which of the following is a valid IP host address given the network ID of 191.254.0.0 while using 11 bits for subnetting? A. 191.254.1.29 B. 191.254.0.32 C. 191.54.1.64 D. 191.254.0.96

A

Which of the following is true for Transport Control Protocol A, Connection oriented B, Process to Process C, Transport layer protocol D, Connectionless

A

Which protocol provides conversion from an IP address to a physical address? A. ARP B. IGRP C. DNS D. ICMP

A

You need to subnet a network that has 5 subnets, each with at least 16 hosts. Which will be your closest choice A. 255.255.255.224 B. 255.255.255.192 C. 255.255.255.240 D. 255.255.255.248

A

( 2 answers ) In Closed-Loop flow control, which of the following mechanism is used in congestion control to regulate the flow from sources into network A. Buffer length B. Link utilization C. Packet header size D. Round-Trip Time

AB

( 2 answers ) In TCP connection management, which of the following statements are true A. Select initial sequence numbers (ISN) to protect against segments from prior connections B. High bandwidth connection pose a problem C. Use global clock to select ISN sequence number D. Time for clock to go through a full cycle should be less than the maximum lifetime of a segment

AB

( 2 answers ) In routing approaches, which of the following statement is true for deflection routing A. Fixed, preset routing procedures B. No route synthesis C. Useful in starting up network D. Predefined source to destination route

AB

( 2 answers ) What are the limitations of RIP protocol A. Limited metric use B. Slow convergence C. Fixed number of hops D. Update message overhead

AB

( 2 answers ) When calculating usable hosts per subnet, the following formula is used 2^bits - 2. For what reason is two subtracted? (choose two) A. Broadcast B. Network C. Unicast D. Multicast

AB

(2 answers) In link state routing, which of the following are possible steps taken to resolve the problem of old update messages A. Add time stamp to each update message B. Add sequence number to each update message C. Add a null number to each update message D. None of the above

AB

Use HDLC and Ethernet to identify similarities between medium access control and data link control protocols. Which of following statements are true? A, Both contains framing information that delineates the beginning and end of each frame. B, Both check the CRC in the received frames for errors C, Both implement error control and flow control for reliable transmission. D, None of the above

AB

Which of the following are advantages of optical fiber A, Noise immunity B, No corrosion C, Extremely low bandwidth D, Wavelength dependency

AB

Which of the following networks use store-and-forward switching operation? A, Computer networks B, Telegraph networks C, Telephone networks D, Wireless Networks

AB

Wireless data communication is compelling, because of A, Its easy and low-cost deployment B, Its support to personal and mobile devices C, Its high reliability to noise and interference D, All of the above

AB

( 3 answers ) In NAT operations, which of the following statements are correct A. NAT maps each private IP address and port number into shared global IP address and available port number B. Hosts inside private networks generate packets with private IP address and TCP/UDP port numbers C. Translation table allows packets to be routed unambiguously D. Translation table allows packets to be routed ambiguously

ABC

In Generic Framing Procedure (GFP), which of the following sentences are correct A, GFP uses a variation of HEC-based self delineation technique B, GFP provides flexible encapsulation framework that supports either a fixed or variable length frame structure C, GFP uses an explicit payload length indicator provided in its frame header to accommodate variable length PDUs D, GFP rely on byte-stuffing mechanism to delineate protocol data units (PDUs)

ABC

( 3 answers ) What are the key mechanisms in Open-Loop Control A. Traffic shaping B. Admission control C. Re-routing D. Policing

ABD

In media access control, which of the following statements are true for Channelization A, Inflexible in allocating bandwidth to users with different requirements B, Does not scale well to large numbers of users C, Widely used in internet traffic D, Inefficient for bursty traffic

ABD

( 2 answers ) In buffer management, which of the following statement is correct for Random Early Detection (RED) technique A. Improves performance of cooperating TCP sources B. Reduce loss probability of misbehaving sources C. Packets produced by TCP will reduce input rate in response to network congestion D. Early drop causes some sources to reduce rate before others, causing gradual reduction in in aggregate input rate

AC

In a transmission system, which of the following statement is true for a receiver A, Receives energy from medium B, Converts information into signal suitable for transmission C, Converts received signal suitable for delivery to user D, All of the above

AC

Which of following statements are true for single-bit parity error detection? A, It can detect all single bit errors in an information frame B, It can detect all double bit errors in an information frame C, It can detect all tripe bit errors in an information frame D, None of the above

AC

Which of the following applications would you select TCP protocol for? A, File transfer B, Domain name service C, Web browsing D, None of the above

AC

( 3 Answers ) The network layer is considered the most complex layer because of the following reasons A. Requires coordinated actions of multiple, geographically distributed network elements B. Responsible for displaying received information to users C. Challenges such as addressing and routing D. User scalability

ACD

( 3 answers ) In Open Shortest Path First (OSPF), which of the following statements are correct A. Enables each router to learn complete network topology B. OSPF typically converges slower than RIP when there is a failure in the network C. Allows routers to build shortest path tree with router as root D. Each router builds an identical link-state database

ACD

In PPP authentication, which of the following is true for Password Authentication Protocol A, After several attempts, LCP closes link B, Initiator and authenticator share a secret key C, Transmitted unencrypted, susceptible to eavesdropping D, Initiator must send ID and password

ACD

( 2 answers ) In Reverse-Path Broadcasting (RPB) scenario, assume each router knows current shortest path to source node. Which of the following statement denotes the router's action A. If shortest path to source is through different port, router drops the packet B. The router stores the packet in a buffer and wait for an explicit routing request from the source C. Upon receipt of a multicast packet, router records the packet's destination address and the forwarding port D. If shortest path to source is through the same port, router forwards the packet to all other ports

AD

Digital communication technologies may introduce errors in communication, which of the following can be used to provide reliable communication A, TCP B, DNS C, UDP D, HDLC

AD

In 802.11 protocol, which of the following statements are true for Basic Service Set (BSS) A, Stations in BSS can communicate with each other B, Multiple BSSs interconnected by Central System (CS) C, Distinct collocated BSS's cannot coexist D, Location in a Basic Service Area (BSA)

AD

Question 6 In PPP authentication, which of the following is true for Challenge-Handshake Authentication Protocol (CHAP) A, Initiator and authenticator share a secret key B, Initiator must send ID and password C, After several attempts, LCP closes link D, Authenticator can reissue challenge during session

AD

A Virtual-Circuit Network (VCN) is normally implemented in the A. session layer B. data link layer C. network layer D. Physical layer

B

A network can receive a multicast packet from a particular source only through a A. designated parent resolve B. designated parent router C. designated protocol router D. None of the above

B

A peer with which a mobile node is communicating is called A. Mobile node B. Correspondent node C. Foreign agent D. Home agent

B

A subset of a network that includes all the routers but contains no loops is called A. Broadcast structure B. spanning tree C. Multi-destination routing structure D. None of the above

B

An end-to-end function is best implemented at a lower level than at a higher level A. True B. False

B

Based on traffic granularity, which of the following levels is traffic management not usually classified into? A. Flow level B. Byte level C. Flow-aggregated level D. Packet level

B

Bootstrap Protocol (BOOTP) allows a diskless workstation to be remotely booted up in a network with TCP port designation for both client and server A. True B. False

B

By Random Early Detection (RED), when a given source transmits at a higher rate than others, the source will A. Achieves a higher bandwidth B. Suffers a higher packet-dropping rate C. Achieves a lower waiting delay D. Suffers a lower packet-dropping rate

B

Congestion control is associated with the window size field A. True B. False

B

Consider a Class B network, where the subnet ID takes 9 bits. What will be the subnet mask? A. 11111111 11111111 11111110 00000000 B. 11111111 11111111 11111111 10000000 C. 11111111 11111111 00000000 00000000 D. None of the above

B

Consider a three hop network from the source to the destination. Let m be the message transmission time at each hop. Let n be the propagation delay of each hop. Assume there is no queueing delay and processing time at each hop. Based on store-and-forward, what is the total time for three packets to be transmitted to the destination by packet pipelining? A. 3m + 3n B. 5m + 3n C. 9m + 9n D. None of the above

B

Consider a token bucket approach for traffic shaping. A token is generated every 5 micro-seconds. Each packet can hold 48 bytes of data. What is the sustainable data transmission rate by the token bucket? A. 7.68 Mbps B. 76.8 Mbps C. 768 Mbps D. None of the above

B

DNS is a domain-name-service that responds to queries of domain name to IP address or IP address to domain name. DNS uses services provided by A, TCP B, UDP C, HTTP D, None of the above

B

Given 3 bits for sequence numbers, what is the maximum sliding window size at the receiver in Go Back 3 ARQ? A, 3 B, 7 C, 8 D, None of the above

B

Given a 7-bit information frame (0, 1, 0, 1, 1, 0, 1), what is the even parity bit? A, 1 B, 0 C, None of the above

B

Given a network address 128.100.0.0, what is its network class type? A. Class A B. Class B C. Class C D. None of the above

B

HDLC is another data link control protocol widely in use. Its framing is based on which of the following? A, Byte stuffing B, Bit stuffing C, Word stuffing D, None of the above

B

How many bits used for header checksum in IPv4 packets? A. 8 bits B. 16 bits C. 32 bits D. None of the above

B

In Asynchronous Transfer Mode (ATM), the packet structure attribute simplifies implementation and ensures high speed transfer A. True B. False

B

In Carrier Sense Multiple Access (CSMA), if station senses medium before trying to use it then chance of collision can be A, Increased B, Reduced C, Doubled D, Highlighted

B

In Ethernet, slot time that is at least the round-trip propagation delay, is the critical system parameter for A, upper bound on time to detect collision B, All of the above C, upper bound on time to acquire channel D, quantum for re-transmission scheduling

B

In FIFO queueing, delay and loss of packets depends on _________ and _________ A. Packet size, sequence number B. inter-arrival, packet lengths C. routing path, sequence number D. RTT value, packet lengths

B

In Go-Back-N ARQ, a procedure where transmission of a new frame is begun before the completion of time of the previous frame transmission is called A, Transitioning B, Pipelining C, Channeling D, None of the above

B

In HDLC frame format, flag is used to identify secondary station (1 or more octets) A, True B, False

B

In Stop-and-Wait protocol, sequence number are not required A, True B, False

B

In a LAN, which address is used to transfer frames to appropriate destination? A, IP address B, Physical address C, Domain name D, None of the above

B

In a collision-free reservation system that has a large number of light-traffic stations, and the delay-bandwidth product is larger than 1. Which of following MAC protocol is a good fit for stations to reserve mini-slots? A, 1-persistent CSMA B, Slotted ALOHA C, CSMA/CD D, None of the above

B

In a distance vector routing, if a link fails A. All routers immediately update their link database and recalculate their shortest path B. Neighboring routers exchange routing tables that may use failed links C. Routers set link distance to infinity and floods the network with an update packet D. All of the above

B

In buffer management, drop priorities requires packet to drop when buffer is full A. True B. False

B

In deflection routing, bufferless operation is considered a disadvantage due to packet loss A. True B. False

B

In general, there are three phases of congestion behavior, i.e., light traffic, knee, congestion collapse. Which phase does TCP congestion avoidance maps to? A. Light traffic B. Knee C. Congestion collapse D. None of the above

B

In infrastructure network supporting voice and data traffic, data traffic is transported through the CP and voice traffic through the CFP A, True B, False

B

In medium access control sublayer, medium usage is mediated by the access control during contention period A, True B, False

B

In multiplexing, Last IN First Out (LIFO) is used to determine the order of packet transmission A, True B, False

B

In networks where errors are infrequent, which approach is favored for efficiency? A, Hop-by-hop approach B, End-to-end approach C, Either one of the above D, Neither one of the above

B

Packet pipelining can lead to latency in message delivery A. True B. False

B

Perform CIDR aggregation on the following /24 IP addresses: 128.58.24.0/24, 128.58.25.0/24, 128.58.26.0/24, 128.58.27.0/24. What is the CIDR outcome? A. 128.58.28.0/22 B. 128.58.24.0/22 C. 128.58.28.0/24 D. None of the above

B

Polling is a scheduling approach for dynamic medium access control. Which of following statements are correct? A, Polling can provide bounds on access delay to the shared medium B, All of the above C, Polling can provide fairness through regulated access opportunities C, Polling performance can deteriorate with large delay-bandwidth product

B

Question 3 In BSD socket API, which type of socket is used to create a UDP socket? A, SOCK_STREAM B, SOCK_DGRAM C, SOCK_RAW D, None of the above

B

Question 5 In BSD socket API, if a client knows the server name but not server's network address, what system call should the client use to get server's network address? A, Connect() B, gethostbyname() C, None of the above D, gettimeofday()

B

Question 8 In twisted pair, a category 5 UTP cable can support a data rate of up to 16MHz A, True B, False

B

Suppose that the ALOHA protocol is used to share a 56 kbps satellite channel. Suppose that frames are 1000 bits long. What is the maximum throughput of the system in number of frames per second. A, 1 frame per second B, 10 frames per second C, 100 frames per second D, None of the above

B

TCP adopts selective repeat ARQ protocol for flow control. In TCP flow control implementation, the window slides at A. Per-packet basis B. Per-byte basis C. Per-bit basis D. None of the above

B

TIMELY provides a framework for rate control that depends on transport layer protocol for reliability A. True B. False

B

The operation of TCP congestion control can be divided into three phases, which phase requires that the congestion window size be increased by one segment upon receiving an ACK from receiver A. Congestion avoidance B. Slow start C. Congestion D. None of the above

B

The simplest approach to queue scheduling is First-In, First-out queueing, where all packet flow make use of different buffer A. True B. False

B

There are similarities between message switching and packet switching. Which of following that applies to packet switching but not to message switching? A, Variable length of information block B, Supporting multiple applications C, Store-and-forward D, All of the above

B

Three or more devices share a link in ________ connection A, Unipoint B, Multipoint C, Point to Point D, None of the above

B

To reduce size of routing table, routers do lookup table on MAC address A. True B. False

B

Upon receipt of a bad segment, UDP? A, It does flow control B, It does not do flow and error control C, It does error control D, Retransmission

B

Using a CIDR notation, a prefix 205.100.0.0 of length 22 is written as 205.100.0.0/22. What network mask that the /22 notation indicates? A. 205.255.255.0 B. 255.255.252.0 C. 255.255.22.0 D. None of the above

B

What is the first valid host on the subnetwork that the node 172.30.190.198/24 belongs to? A. 172.30.190.0 B. 172.30.190.1 C. 172.30.190.100 D. None of the above

B

What is the primary function of medium access control? A, It is to deal with the flow control of a shared communication link. B, It is to minimize or eliminate the incidence of collisions of a shared communication link. C, It is to deal with the congestion control of a shared communication link. D, None of the above

B

What is the root problem of link state routing? A. Counting to infinity B. Flooding overhead C. Slow reaction to link failures D. All of the above

B

What is the security requirement in case of Denial of Service? A. Privacy B. Availability C. Integrity D. None of the above

B

What is the subnetwork number of a host with an IP address of 172.16.66.0/21 A. 172.16.48.0 B. 172.16.64.0 C. 172.16.0.0 D. 172.16.36.0

B

What is the vulnerable period of collisions in Slotted ALOHA? A, Round-trip propagation delay B, One frame transmission time C, Two frame transmission time D, None of the above

B

What was the concern of the telephone system that motivated the ARPANET design? A, Scalability B, Vulnerability C, Efficiency D, None of the above

B

When a TCP client initiates a three-way handshake with a sequence number x, what will be the acknowledgement number when the TCP server replies? A. x B. x + 1 C. x + y (where y is the sequence number proposed by TCP server) D. None of the above

B

When three duplicate acknowledgements arrive before timeout expires, what will TCP congestion control algorithm reset congestion threshold to for fast re-transmission and fast recovery? A. Reset congestion threshold to 1 B. Reset congestion threshold to half of the current congestion window size C. Reset congestion threshold to the current congestion window size D. None of the above

B

Which ARQ flow control protocol is used by TCP? A, Stop-and-Wait B, Selective Repeat C, Go-back-N D, None of the above

B

Which of following is not a packet-level mechanism? A. Fair queueing B. Token bucket shaping C. Head-of-line priority queueing D. Random early detection

B

Which of following is the implementation of link state approach in the IP routing protocol? A. RIP B. OSPF C. BGP D. None of the above

B

Which of following issue exists in virtual-circuit subnet but not in datagram subnet? A. Addressing B. State information C. Routing D. None of the above

B

Which of following networks represents an example of virtual circuit switching at the network layer? A. IP B. ATM C. Both of the above D. All of the above

B

Which of following protocol allows a host to signal its multicast group membership to its attached routers? A. ICMP B. IGMP C. OPSF D. None of the above

B

Which of following protocol is HTTP built upon? A, IP B, TCP C, UDP D, SMTP

B

Which of following statements identifies the similarity between HDLC (data link control) and Ethernet (medium access control) A, All of the above B, Both contain framing information that delineates the beginning and end of each frame C, Both implement error control and flow control functions to provide reliable transmission D, Both provide connection-oriented packet transfer services to the network layer

B

Which of the following features are true for asynchronous transfer mode (ATM)? A. It supports quality of service B. All of the above C. It only supports fixed-length packets D. It is connection-oriented

B

Which of the following functions can a home router perform? A. Private IP addresses in home by network address translation B. All of the above C. Local area network access using WiFi D. Single global IP address using DHCP

B

Which of the following is a feature of fair queueing A. Every user flows share the same logical buffer B. Idealized system assumes fluid flow from queues C. Addresses different users by order or request D. None of the above

B

Which of the following packet header length cannot be used in an IPv4 packet header? A. 20 Bytes B. 30 Bytes C. 60 Bytes D. 64 Bytes

B

Which of the following statements is true about the stop-and-wait ARQ protocol? A, Stop-and-wait is only efficient if the link delay-bandwidth product is large B, Stop-and-wait is only efficient if the link delay-bandwidth product is small C, Stop-and-wait is only efficient if the link bandwidth is low D, Stop-and-wait is only efficient if the link bandwidth is high

B

Which of the following statements is wrong about fair queuing? A. Fair queueing is a packet-level traffic management B. Fair queueing attempts to provide equal-size buffers to flows C. Fair queueing attempts to provide equitable access to transmission bandwidth D. All of the above

B

Which one of the following event is not possible in wireless LAN. A, Acknowledgement of data frames B, Collision detection C, Multi-mode data transfer D, Collision avoidance

B

Which protocol is used to assign temporary IP addresses to hosts? A. ICMP B. DHCP C. ARP D. None of the above

B

in practical IPv6 application, a technology encapsulates IPv6 packets inside IPv4 packets, this technology is called A. Routing B. IP tunneling C. Network address translation D. Dynamic host configuration protocol

B

Consider a Gigabit Ethernet hub with stations at a 100-meter distance and average frame size of 512 bytes. Assume the propagation speed is at 2/3 of light speed. What is the value of normalized delay-bandwidth product? A, 0.0122 B, 0.122 C, 1.22 D, None of the above

B Normalized delay-bandwidth product equals to (Propagation delay / Frame transmission time). Propagation delay = 5*10^-7. Frame transmission time is 512 * 8 / 10^ 9.

( 2 Answers ) One can use repeaters, bridges and routers to interconnect two LANs. Which of the following approaches will make local traffic stay in its own LAN? A. repeaters B. routers C. bridges D. All of the above

BC

In peer-to-peer protocol, the purpose of Automatic Repeat Request is A, to ensure a sequence of information packet is delivered with an ACK request B, to ensure a sequence of information packet is delivered in order C, to ensure a sequence of information packet is delivered without errors or duplication despite transmission errors and losses D, to ensure a sequence of information packet is delivered out-of-order

BC

Which of the following is true for two-dimensional parity check A, Arrange information in rows B, More parity bit to improve coverage C, Arrange information in columns D, Add multiple parity bits to each column

BC

Which of the following networks can be connection-oriented? A, Telegraph networks B, Computer networks C, Telephone networks D, All of the above

BC

( 3 answers ) Which fields in IP packet provide for fragmentation of datagrams to allow differing MTUs in the internet A. Type of service B. Fragmentation offset C. Identification D. Flags

BCD

In media sharing techniques, which of the following are channelization approaches A, Data Division Multiple Access B, Time Division Multiple Access C, Code Division Multiple Access D, Frequency Division Multiple Access

BCD

A host in an organization has an IP address 150.32.64.34 and a subnet mask 255.255.240.0. What is the address of this subnet? A. 150.32.64.16 B. 150.32.64.24 C. 150.32.64.0 D. 150.32.64.32

C

An IP address associated with a mobile node while visiting a foreign link A. Handover address B. Home address C. Care of address D. Home link

C

Assume bit errors occur at random. If each bit has 50% probability to be in error by transmission. What is the probability of a four-bit frame to be in error by transmission? A, 1/4 B, 1/8 C, 1/16 D, None of the above

C

Consider a bulk data transfer application where a server sends a large file that is segmented in a number of full-size packets that are to be transferred to the client. Assume the channel has a low probability of error. Which of following strategies for sending ACK frames in a Go-Back-N is appropriate for the situation? A, send an ACK frame when the next piggyback opportunity arises B, send an ACK frame immediately after each frame is received C, send an ACK frame after every other frame is received D, Any one of the above

C

Consider a situation where an interactive application produces a packet to send each keystroke from the client and the server echoes each keystroke that it receives from the client. Which of following strategies for sending ACK frames in a Go-Back-N is appropriate for the situation? A, send an ACK frame immediately after each frame is received B, send an ACK frame after every other frame is received C, send an ACK frame when the next piggyback opportunity arises D, Any one of the above

C

Consider a three hop network from the source to the destination. Let m be the packet transmission time at each hop. Let n be the propagation delay at each hop. Assume there is no queuing delay and processing time at each hop. Based on store-and-forward, what is the total time for the packet to be transmitted to the destination? A. m + n B. 3m + n C. 3m + 3n D. None of the above

C

Consider building a CSMA/CD network running at 1Gbps over a 1-km cable. The signal speed in the cable is 200,000 km/sec. What is the minimum frame size? A, 64 Bytes B, 640 Bytes C, 1250 Bytes D, None of the above

C

Ensuring that information is not altered during transfer is associated with A, Authentication B, Confidentiality C, Integrity D, Availability

C

For a 10Mbps Ethernet link, if the length of the packet is 32bits, the transmission delay is(in microseconds) A. 0.32 B. 320 C. 3.2 D. 32

C

If the probability of error is very low in a communication link, which of the following statements is true about performance of ARQ protocol? A, Stop-and-wait and Go-back-N ARQ protocols have similar performance B, Stop-and-wait and Selective Repeat ARQ protocols have similar performance C, Go-back-N ARQ and Selective Repeat ARQ protocols have similar performance D, None of the above

C

In a router, the control of the transmission rate at the sender's side such that the router's buffer will not be over-filled is called _________ if sender is transmitting too fast A. Network under-utilization B. Host flooding C. Network congestion D. None of the above

C

In buffer management, which feature requires packet to drop when buffer is full A. Drop priorities B. Fairness C. Drop strategy D. Aggregation

C

In multicast communication, relationship is A. one to one B. many to one C. one to many D. one to all

C

In order to maximize the usage of limited IP addresses, which of the following protocol is commonly used A. NAT B. DHCP C. Both of the above D. None of the above

C

In the layer hierarchy as the data packet moves from the upper to the lower layers, headers are A, Removed B, Modified C, Added D, Rearranged

C

In the scenario above, what should be the value of frame number y at receiver B? A, 3 B, 8 C, 7 D, None of the above

C

It is possible for a network layer to provide a choice of services to the user of the network. Which of following the IP network layer offers A. All of the above B. connection-oriented transfer of packets with delay guarantee C. Best-effort connectionless service D. connection-oriented reliable stream service

C

Of the following network layer functions, which one is optional? A. Routing B. Forwarding C. Congestion control D. None of the above

C

Packet is to be forwarded to a network with MTU of 592 bytes. The packet has an IP header of 20 bytes and a data part of 1484 bytes. Which of following maximum data length per fragment is legitimate? A. 592 B. 572 C. 568 D. 562

C

Question 2 Suppose an application layer entity wants to send an L-byte message to its peer process, using an existing TCP connection. The TCP segment consists of the message plus 20 bytes of header. The segment is encapsulated into an IP packet that has an additional 20 bytes of header. The IP packet in turn goes inside an Ethernet frame that has 18 bytes of header and trailer. What is the bandwidth utilization in terms of the percentage of the transmitted bits in the physical layer corresponds to message information if L = 500 bytes? A, 100% B, 70% C, 90% D, 80%

C

The ________ is the physical path over which a message travels A, Protocol B, Route C, Medium D, Path

C

Transmission Control Protocol (TCP), has same Checksum controlling like A. TCP/IP B. ICMP C. UDP D. IP

C

What information is used as the entry of the lookup table in a Network Address Translation box? A. UDP port number B. IP address C. All of the above D. TCP port number

C

What is the binary sequence that corresponds to polynomial code X^3 + x^2 + 1? A, 1110 B, 0111 C, 1101 D, 111

C

What is the dotted notation of an IP address of 10000000 10000111 01000100 00000101 ? A. 128.135.65.5 B. 128.135.65.5 C. 128.135.68.5 D. 128.133.68.5

C

What is the maximum number of IP addresses that can be assigned to hosts on a local subnet that uses the 255.255.255.224 subnet mask A. 14 B. 15 C. 30 D. 62

C

What is the vulnerable period of collisions in ALOHA? A, Round-trip propagation delay B, One frame transmission time C, Two frame transmission time D, None of the above

C

Which component of NFV comprises of hardware and software required to deploy, manage and execute VNFs. A. Network function B. Network function modules C. NFVI D. None of the above

C

Which layer LAN bridges work on? A. Transport layer B. Network layer C. Medium access control D. None of above

C

Which of following describe benefits of flooding, a specialized routing approach? A. No routing table needed for routers B. Useful in propagating information to all nodes C. All of the above D. Always reach the destination by the fastest path

C

Which of following fields that IPv6 dropped from IPv4? A. Header length B. Header checksum C. All of the above D. ID/flags/frag offset

C

Which of following information is not used in UDP de-multiplexing? A. Source IP address B. Destination IP address C. Source port number D. Destination port number

C

Which of following is the range of IPv4 addresses spanned by Class C? A. 1.0.0.0 to 127.255.255.255 B. 128.0.0.0 to 191.255.255.255 C. 192.0.0.0 to 223.255.255.255 D. None of the above

C

Which of following statements about leaky bucket is wrong? A. In leaky bucket, when the bucket is full, the new arriving packets may be discarded B. Leaky bucket is a flow-level traffic management mechanism C. In the leaky bucket, the packet output rate can be variable D. In the leaky bucket, the packet output rate is always constant

C

Which of following statements are true about framing protocols? A, PPP uses character-based framing which requires byte stuffing B, HDLC uses Flag-based framing which required bit stuffing C, All of the above D, None of the above

C

Which of following statements is true for FIFO queueing? A. In FIFO queueing, all packet flows share the same buffer B. FIFO queueing cannot provide differentiated QoS to packet flows C. All of the above D. In FIFO queueing, arriving packets will be discarded if the buffer is full

C

Which of the basic elements of ARQ is associated with negative acknowledgement A, Timeout mechanism B, ACKs C, NAKs D, Error detecting code

C

Which of the following is not a general misconception of SDN? A. SDN is a mechanism B. SDN is an open API for that provides standard interface for programming switches C. SDN is a framework to solve a set of problems D. All of the above

C

Which of the following is provided at the IP layer A. Connectionless B. Best effort delivery service C. Both of the above D. None of the above

C

Which of the following statement is correct for IPv6 A. Addresses are not hierarchical and are randomly assigned B. There are 2.7 billion available addresses C. Broadcast in IPv4 have been replaced with multicast in IPv6 D. Does not support multiple multiple IPv6 address per interface

C

Which of the following statements are true for PPP byte stuffing A, Malicious users may inflate bandwidth B, Size of frame varies unpredictably due to byte insertion C, All of the above D, None of the above

C

Which protocol glues the network of networks together as the Internet? A, TCP B, UDP C, IP D, None of the above

C

Why not use CSMA/CD in a wireless LAN? The primary reason is A, The round-trip delay in a wireless LAN is too large B, The frame is usually very small in a wireless LAN C, The hidden station problem D, All of the above

C

( 2 answers ) In Head of Line (HOL) priority queueing, which of the following statement is true for this approach A. High priority queue has higher waiting time B. Buffers can be dimensioned for different loss probabilities C. High priority queue has lower waiting time D. High priority queue services until empty

CD

( 2 answers ) Which of these statements are true of IPv6 representation A. The first 64 bits represent the dynamically created interface ID. B. Leading zeros in an IPv6 16 bit hexadecimal field are mandatory C. A single interface may be assigned multiple IPv6 addresses of any type D. Every IPv6 interface contains at least one loopback address

CD

Which of the following are management services offered by the MAC sublayer in wireless LAN A, Network management B, Storage management C, Roaming within ESS D, Power management

CD

A network used to join the individual networks at different sites into one extended network is called A, PAN B, LAN C, SAN D, VPN

D

A protocol is a set of precise and unambiguous rules that governs A, How two or more communicating entities in a layer are to interact B, Messages that can be sent and received C, Actions that are to be taken when a certain event occurs D, All of the above

D

A service offered at a given layer can include which of the following feature(s) A, Sequencing B, Reliability C, Timing D, All of the above

D

A transparent bridge's duties include A. Forwarding B. Blocking C. Filtering frame D .All of the above

D

Assume a TCP source writes a 1200-byte message in one write. Which of following is possible for the destination to receive the message? A. It receives three reads of 400 bytes each B. It receives two reads of 600 bytes each C. It receives a 1200-byte message in one read D. All of the above

D

Bluetooth is an example of A, Local Area Network B, Wide Area Network C, Metropolitan Area Network D, Personal Area Network

D

By framing, frame boundaries can be determined using A, Character Counts B, Control Characters C, Flags D, All of the above

D

Flooding may easily swamp the network as one packet creates multiple packets, possibly in exponential growth rate. What are possible means to reduce resource consumption in the network? A. Use a time-to-live field in each packet to limit its lifetime B. Add a unique identifier to a packet for removing its duplicate C. Use address and sequence number to discard duplicates D. All of the above

D

Given 3 bits for sequence numbers in Selective Repeat ARQ. If the sender already set the sliding window size to be 4, what is the maximum sliding window size at the receiver? A, 3 B, 8 C, 7 D, None of the above

D

How many hosts can be addressed on 10.0.0.0/16? A. 16 B. 254 C. 65536 D. 65534

D

IPv6 has a much larger space of A. 2^8 B. 2^16 C. 2^32 D. 2^128

D

In Asynchronous Transfer Mode (ATM), which of the following is an examples of supported services A. Real time voice and video B. Circuit emulation for digital transport C. Data traffic with bandwidth guarantees D. All of the above

D

In BSD socket API, which system call is used to assign a network address to the socket? A, listen() B, None of the above C, connect() D, bind()

D

In Carrier Sense Multiple Access/Collision Detection (CSMA/CD), to continue transmission process we use a A, Signal B, Station C, Access point D, Loop

D

In IP network, which of the following statement is incorrect A, Packets can arrive out-of-order B, Packets can arrive with errors or be lost C, Packets can arrive after long delays D, Packets always arrive on time

D

In RIP operation, which of the following statement is correct A. Router sends update message to neighbors every 30 sec B. To deal with changes in topology such as a link failure, a router expects an update from each of its neighbors within 180 sec C. Convergence speed up by triggered updates D. All of the above

D

In a router, which of the following statement is true for creating routing tables A. Need information on state of links B. Need to distribute link state information using a routing protocol C. Need to compute routes based on information D. All of the above

D

In error detection and loss recovery, which of the following statement is correct A, Frames may undergo errors in transmission B, CRCs detect errors and such frames treated as lost C, Frames lost due to loss-of-synchronization or receiver buffer overflow D, All of the above

D

In internet, switching is done by using datagram approach to packet switching at the A. Data link layer B. Application layer C. Physical layer D. Network layer

D

In network layer, which of the following statement is true for packet networks A. Individual packet streams are highly bursty B. User demand can undergo dramatic change C. Internet structure is highly decentralized D. All of the above

D

In phases of congestion behavior, when arrival rate is greater than outgoing line bandwidth A. Knee B. Congestion onset C. Light traffic D. Congestion collapse

D

Of the following services, which service(s) does the IP layer provides? A, Error control B, Flow control C, Connection-based data transfer D, None of the above

D

Question 4 Which feature does the data link layer and transport layer have in common? A, Medium access control B, All of the above C, Congestion control D, Flow control

D

Question 9 What is the binary equivalent of the following polynomial arithmetic x^7 + x^6 + x^5 + x^2 + 1 A, 11101101 B, 11100111 C, 11011101 D, 1100101

D

Random access is also called the A, Controlled access B, Channelization C, Authentication D, Contention methods

D

TCP header has a field called window size. What value is the value window size set to? A. Advertised window size for congestion control B. Round-trip delay C. Advertised window size for flow control D. None of the above

D

The disadvantage of Stop-and-Wait protocol A, Error free communication channel does not exist B, Acknowledgement may get lost C, Deadlock situation may occur D, All of the above

D

The functionalities of presentation layer includes A, Data compression B, Data encryption C, Data decryption D, All of the above

D

This layer is an addition to OSI model A, Application layer B, Presentation layer C, Session layer D, Presentation layer and Session layer

D

Upon which of the following condition is token bucket and leaky bucket the same? A. Leaky bucket size is zero B. Token bucket size is infinite C. Leaky bucket size is infinite D. Token bucket size is zero

D

Use IEEE 802.3 and IEEE 802.11 to discuss differences between wired and wireless LANs. Which of following statements are true about the differences? A, Station mobility B, Error rate C, Collision detection D, All of the above

D

Using Euclidean Division, what will be the remainder of 70 by 999 where 70 is the divisor and 999 is the dividend A, 17 B, 14 C, 21 D, 19

D

What are possible metrics for routing? A. Hop count B. Delay C. Bandwidth D. All of the above

D

What are typical end-to-end Quality-of-Service factors? A. Jitter B. Packet delay C. Packet loss rate D. All of the above

D

What is the security requirement in case of Malicious Code? A. Privacy B. Availability C. Integrity D. All of the above

D

What is the vulnerable period of collisions in Carrier Sense Multiple Access (CSMA)? A, One frame transmission time B, None of the above C, Round-trip propagation delay D, One propagation delay

D

Which OSI layer is responsible for dividing the transmitted bit stream into frames? A, Network layer B, Transport layer C, Application layer D, Data link layer

D

Which class of IP address does the reverse-path broadcasting uses? A. Class A B. Class B C. Class C D. Class D

D

Which multiple access technique is used by IEEE 802.11 standard for wireless LAN? A, ALOHA B, CDMA C, CSMA/CD D, CSMA/CA

D

Which of following control is enabled in UDP? A. Flow control B. Error control C. Congestion control D. None of the above

D

Which of following describe general goals in a routing algorithm? A. Rapid responsiveness to network changes B. Robustness under high load and link failure C. Low overhead for implementation D. All of the above

D

Which of following describe the benefits of link state routing compared to distance vector routing? A. Fast convergence B. Support for multiple metrics C. Support for multiple paths to a destination D. All of the above

D

Which of following requirements are necessary for packet networks to support multiple and diverse applications? A, Transfer arbitrary message size B, Low delay for interactive applications C, Packets have maximum length D, All of the above

D

Which of following services belong to the data link layer? A, Insert framing information into the transmitted stream to indicate the boundaries that define frames B, Provide error control to ensure reliable transmission C, Provide flow control to prevent the transmitter from overrunning the receiver buffer D, All of the above

D

Which of following statements are true for HDLC? A, supports various data transfer modes B, supports multi-point links and point to point links C, implements error control and flow control mechanisms D, All of the above

D

Which of following statements are true for two-dimensional parity error detection? A, It can detect all single bit errors in an information frame B, It can correct all single bit errors in an information frame C, It can detect all double bit errors in an information frame D, All of the above

D

Which of the following are features of ARPANET design? A, Connectionless packet transmission B, Routing tables at the packet switches C, Destinations identified by unique addresses D, All of the above

D

Which of the following is a type of router defined in OSPF A. Internal router B. Area border router C. Backbone router D. All of the above

D

Which of the following is an essential network function A. Forwarding B. Routing C. Priority and scheduling D. All of the above

D

Which of the following is not true for MAC scheduling A, More efficient channel utilization B, Less variability in delays C, Can provide fairness to stations D, Reduced computational or procedural complexity

D

Which of the following is true about the ways in which the OSI reference model and TCP/IP reference model differ. A, They differ in the number of layers B, TCP/IP model does not have presentation layer, but OSI model has C, TCP/IP model does not have session layer, but OSI model has D, All of the above

D

Which of the following protocols work at IP layer? A. ICMP B. ARP C. IGMP D. All of the above

D

Which of the following services are provided by UDP A. IP B. De-multiplexing C. Error Checking D. All of the above

D

Which of the following statement is true for DHCP A. Used extensively to assign temporary IP addresses to hosts B. Allows ISP to maximize usage of their limited IP addresses C Time threshold to enforce lease time D. All of the above

D

Which of the following statement is true for optical fiber A, Plentiful bandwidth for new services B, Dominates long distance transmission C, Distance less of a cost factor in communications D, All of the above

D

Which of the following statements are true for the best-effort service of IP? A, Packets can arrive with errors or be lost B, Packets can arrive out-of-order C, Packets can arrive after very long delays D, All of the above

D