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Correct answer is (d) Error control

To elaborate: Application layer is the topmost layer in the OSI model. Network VIRTUAL TERMINAL, mail service, FILE transfer, access and management are all services of the application layer. It uses PROTOCOLS like HTTP, FTP, and DNS etc. to provide these services.

Correct option is (a) PACKET switching

Explanation: In packet switching, the bits are received in out of order and need to be assembled at the receiver end, whereas in the case of CIRCUIT switching, all the bits are received in order. All TRANSMISSIONS may not OCCUR through the same path in case of packet switching.

The correct answer is (b) guaranteed CONSTANT rate

The best I can explain: Circuit switching is connection oriented and is always implemented in the physical LAYER. Once a path is SET, all transmission occurs through the same path. It is used SINCE the early times in telephonic systems.

The correct choice is (b) Circuit switching

The best I can EXPLAIN: In circuit switching, a physical path between the sender and receiver is established. This path is maintained until the connection is needed. Circuit switching is implemented in the Physical layer and is USED in telephonic SYSTEMS.

The correct choice is (d) PACKET switching and Circuit switching

The best explanation: Packet switching and Circuit switching are two DIFFERENT TYPES of switching methods used to connect the MULTIPLE communicating devices with one another. Packet switching is used in conventional LAN systems and circuit switching is used in telephonic systems.

Right answer is (b) (N*L)/R

The best explanation: The equation to FIND the END to end delay when no. of BITS, transmission rate and no. of routers is given by (N*L)/R. The total end to end delay, that is, nodal delay is the sum of all, the PROCESSING delay, QUEUING delay, transmission delay and propagation delay.

Right ANSWER is (B) CIRCUIT switched

Best explanation: Circuit switching is connection oriented switching technique, whereas in the case of packet switching, it is connectionless. Circuit switching is implemented in the Physical layer, whereas packet switching is implemented in the NETWORK layer. Internet too is based on the concept of circuit switching.

The CORRECT choice is (d) All of the mentioned

The explanation is: RADIO CHANNELS can PENETRATE walls, can be used to provide connectivity to mobile users and can also carry signals for long DISTANCES.

Correct option is (d) All of the MENTIONED

For EXPLANATION I would say: In fibre optics the TRANSMISSION of information is in the form of light or photons. Due to all above properties mentioned in options fibre optics can be submerged in WATER and are used at more risk environments.

Right CHOICE is (b) 2

The best I can EXPLAIN: Coaxial cable has an inner conductor surrounded by a insulating layer, which is surrounded by a conducting SHIELD. Coaxial cable is used to carry high FREQUENCY signals with low LOSSES.

Right ANSWER is (C) WIRELESS LAN

The best explanation: Wireless LAN is unguided MEDIA.

The correct answer is (a) UDP TRAFFIC

Explanation: UDP is more VULNERABLE to attacks, so FIREWALLS are often configured to BLOCK suspicious UDP traffic.

Correct choice is (d) SWITCHED network

Easiest explanation: Switches make sure that the PACKET is sent to the INTENDED receiver and no one else, thus preventing Sniffers to perform their function. Intelligent switches are hence used preferably for the network.

Right option is (b) Passive receiver

The best explanation: The function of PACKET sniffers is to just silently RECEIVE the packets flowing in the CHANNEL. If they inject any packets into the channel, they might alert the other USERS about the intrusion.

The CORRECT choice is (b) Bandwidth flooding

Explanation: In Bandwidth flooding, the attacker FLOODS the victim machine with a DELUGE of packets to MAKE sure that no bandwidth is available. The victim then cannot utilize the complete bandwidth to perform its operation.

Right ANSWER is (c) Connection flooding

To elaborate: In Vulnerability attack, the attacker EXPLOITS the VULNERABLE control points of the network to deny access to the victims. In Bandwidth flooding, the attacker intentionally USES up all the bandwidth by flooding the victim with a deluge of packets and makes sure that the victim can’t USE any bandwidth. In UDP flooding, too many UDP packets are sent by the attacker to the victim at random ports.

The correct option is (d) All of the mentioned

Easiest explanation: In a DoS attack, the attacker won’t let the victims access the network by using a CERTAIN method that ensures that an essential network resource is unavailable to the victim. In vulnerability attack, the attacker exploits any OBVIOUS vulnerable entity in the network to deny the victim access into the network. In BANDWIDTH flooding, the attacker floods the victim with a huge flow of packets and uses up all the bandwidth. In connection flooding, the attacker floods the victim network with a huge number of connections, so that, no other machine can CONNECT to it.

Correct choice is (b) Botnet

The best I can explain: Botnet is a NETWORK of COMPROMISED devices used by the attacker without the owner’s knowledge to PERFORM unethical activities such as spamming. The attacker usually uses the least SECURE devices to create the botnet.

Right option is (B) ETHERNET

For EXPLANATION: Collision detection is not possible in Ethernet without extensions. Collision detection TECHNIQUES for multiple access like CSMA/CD are used to detect collisions in the Ethernet architecture.

Correct option is (d) 10000 Mbps

For explanation: Fiber channel speeds have been increasing over the years. 10000 Mbps is the max data TRANSFER RATE for optical fiber cables. It is said to be the fastest among the other kinds of cables like STP cables and co-axial cables. PEOPLE are now using optical fiber cables instead of STP cables for LANs due to their fast data transfer CAPABILITY.

The CORRECT answer is (b) Hub/switch

For explanation I would say: In STAR topology, no computer is connected to ANOTHER computer directly but all the computers are connected to a central switch or hub. EVERY message sent from a source computer goes through the switch or hub and the switch or hub then forwards the message only to the INTENDED destination computer.

Right answer is (C) RJ-45

For explanation: RJ-45 is used for STP CABLE. 100 Mbps is the max data transfer RATE that can be handled by STP. RJ-45 is popularly used to connect to modern-day routers, computer network cards, and other network devices.

The correct answer is (b) 100 MBPS

The best explanation: 100 Mbps is the MAX DATA transfer rate that can be handled by STP cables, and its default connector is RJ-45. 100 Mbps is a feasible data transfer rate for small networks LIKE LANs.

Correct choice is (c) 100 m

Explanation: The MAX the Shielded TWISTED PAIR cable is 100 METERS. If the length exceeds 100 meters, the loss of signals flowing through the cable would be really high. Thus, STP cable is more suitable for smaller networks like LANs.

The correct choice is (b) Security management

To explain: The Security management portion of LAN management SOFTWARE RESTRICTS access, RECORDS user ACTIVITIES, and audit data. It is responsible for controlling access to the network based on predefined policy. The security management ENSURES authentication, confidentiality, and integrity in the LAN.

Correct answer is (a) LAN intrinsic software

To explain: A standalone program that has been modified to work on a LAN by including CONCURRENCY controls such as file and record LOCKING is an EXAMPLE of LAN intrinsic software. They are used to GIVE better FUNCTIONALITY of the program and the applications working over it to the users of the LAN.

Correct answer is (a) SHIELDED Twisted Pair Cable

The best explanation: For physical media, STP cable stands for Shielded twisted pair cable. 100 MBPS is the max data capacity of STP cable and its default connector is RJ45. It is popularly USED in LANs due to its ease of maintenance and installation.

The correct answer is (c) FILE server

The explanation is: A file server allows LAN users to share computer PROGRAMS and data. It uses the File Transfer PROTOCOL to provide this feature on ports 20 and 21. The file server works as a medium for the transfer.

The correct answer is (c) Distance between the routers

To explain: Propagation delay is caused when the packet is in its electric signal form and is travelling through a MEDIUM (a wire or a electromagnetic WAVE). Propagation delay is the time it takes a bit to propagate from one router to the NEXT. If the distance between the routers is increased, it will take LONGER time to propagate, that is, there would be more propagation delay.

Right CHOICE is (B) Distance between the routers

Easiest EXPLANATION: TRANSMISSION delay = packet length / transmission rate. The transmission rate DEPENDS upon the bandwidth of the medium.

Right option is (B) QUEUING DELAY

The BEST I can explain: Since there is no other packet to be transmitted, there is no NEED for a queue. Therefore, the delay caused due to the queuing would be none i.e. 0.

The correct choice is (C) dnodal = dproc + dqueue + DTRANS + dprop

For explanation I would say: The total node-to-node delay, that is, nodal delay is the sum of all, the processing delay, queuing delay, transmission delay and PROPAGATION delay. Ideally, the nodal delay must be LOW as possible for a BETTER Quality of Service of the network.

Right option is (c) N-1

The best I can explain: In the equation N (dproc + dtrans + dprop), N is the NUMBER of checkpoints/stops that the packet makes as it REACHES the destination. The stops are made at each router and the final destination NODE. Now, since N = number of routers + final node, then number of routers = N – final node. As we know, there is only 1 final node in a PATH, thus, number of routers = N – 1. Suppose, There is a path A->R1->R2->B for a packet where A is the SOURCE node, B is the final node and R1 and R2 are routers. The total delay would be given by N (dproc + dtrans + dprop) where N = 3, since the packet would stop at R1, R2 and B. The number of routers here are 2, and (N – 1) is also 2.

The correct answer is (b) 10Mbps

To ELABORATE: The THROUGHPUT is generally the transmission RATE of BOTTLENECK LINK.

The correct choice is (a) PROCESSING delay

The best I can explain: Processing delay is INDUCED at a ROUTER’s or other network processor’s end in the path of the PACKET and is caused by the TIME taken by the processor to examine the packet’s header to decide the further path of the packet.

The correct option is (d) All of the mentioned

Explanation: When a packet has to TRAVEL from ONE end system to another, it first FACES the queuing delay when there are multiple PACKETS which are to be sent, then it faces the transmission delay to convert the packet into bits to be transmitted, and then it faces the propagation delay to propagate the bits through the PHYSICAL medium.

Correct CHOICE is (b) Frames

The best I can explain: TDM is the abbreviation for Time division multiplexing. It is technique for combining several low rate CHANNELS to a single high rate channel. For a certain time slot, the several channels COULD use the MAXIMUM bandwidth. Each channel is inactive for a period of time too. Some other multiplexing techniques are FREQUENCY division multiplexing and Phase division multiplexing.

Right option is (a) Greater than

Explanation: In TDM the transmission rate provided by the path that is multiplexed will always be greater than the SUM of transmission rates of the single SOURCES. This happens because the transmission rate is provided to each source only for a small period of TIME.

Right answer is (d) Both Efficiency & Privacy

The best explanation: Multiplexing helps US to TRANSFER our messages over a shared channel. This brings up the issue of privacy and efficiency. Fortunately, Multiplexing has HIGH efficiency and high privacy when implemented because in the implementation, the transport layer of the OSI network model handles the function of multiplexing through interfaces called ports which provide the required efficiency and privacy.

Correct option is (c) Silent period

For explanation: There are instances when connection between two endpoints has been established, but no communication or TRANSFER of messages OCCURS. This period of time is called silent period. The silent period ends when EITHER of the two endpoints STARTS the communication.

Correct answer is (a) 32kbps

For explanation I would SAY: TRANSMISSION rate= frame rate * NUMBER of bits in a SLOT.

Given: Frame rate = 4000/sec and number of bits in slot = 8

Thus, Transmission rate = (4000 * 8) BPS

= 32000bps

= 32kbps

The correct CHOICE is (a) n

Explanation: In TDM, the total unit of time is DIVIDED equally among all the signal sources and each and every SOURCE has ACCESS to the complete channel bandwidth during its allotted time slot. When the time slot of the source is not active, it remains idle and waits for its slot to begin.