laboursonline – MCQs, Mock Tests | Gate GATE STUDY MATERIAL /NETWORKING SET 3

In the following pairs of OSI protocol layer/sub-layer and its functionality, the INCORRECT pair is

1. Network layer and Routing
2. Data Link Layer and Bit synchronization
3. Transport layer and End-to-end process communication
4. Medium Access Control sub-layer and Channel sharing

✅ Correct Answer: 2

Choose the best matching between Group 1 and Group 2. Group-1 Group-2 P. Data link 1. Ensures reliable transport of data over a physical point-to-point link Q. Network layer 2. Encoder/decodes data for physical transmission R. Transport layer 3. Allows end-to-end communication between two processes 4. Routes data from one network node to the next

1. P-1, Q-4, R-3
2. P-2, Q-4, R-1
3. P-2, Q-3, R-1
4. P-1, Q-3, R-2

✅ Correct Answer: 1

Which of the following is NOT true with respect to a transparent bridge and a router?

1. Both bridge and router selectively forward data packets
2. A bridge uses IP addresses while a router uses MAC addresses
3. A bridge builds up its routing table by inspecting incoming packets
4. A router can connect between a LAN and a WAN

✅ Correct Answer: 2

Host A sends a UDP datagram containing 8880 bytes of user data to host B over an Ethernet LAN. Ethernet frames may carry data up to 1500 bytes (i.e. MTU = 1500 bytes). Size of UDP header is 8 bytes and size of IP header is 20 bytes. There is no option field in IP header. How may total number of IP fragments will be transmitted and what will be the contents of offset field in the last fragment?

1. 6 and 925
2. 6 and 7400
3. 7 and 1110
4. 7 and 8880

✅ Correct Answer: 3

Since it is a network that uses switch, every packet goes through two links, one from source to switch and other from switch to destination. Since there are 10000 bits and packet size is 5000, two packets are sent. Transmission time for each packet is 5000 / 10^7 bits per second links. Each link has a propagation delay of 20 microseconds. The switch begins forwarding a packet 35 microseconds after it receives the same. If 10000 bits of data are to be transmitted between the two hosts using a packet size of 5000 bits, the time elapsed between the transmission of the first bit of data and the reception of the last bit of the data in microseconds is _________.

1. 1075
2. 1575
3. 2220
4. 2200

✅ Correct Answer: 2

Which one of the following statements is FALSE?

1. TCP guarantees a minimum communication rate
2. TCP ensures in-order delivery
3. TCP reacts to congestion by reducing sender window size
4. TCP employs retransmission to compensate for packet loss

✅ Correct Answer: 1

Which one of the following statements is FALSE?

1. HTTP runs over TCP
2. HTTP describes the structure of web pages
3. HTTP allows information to be stored in a URL
4. HTTP can be used to test the validity of a hypertext link

✅ Correct Answer: 2

A serial transmission Ti uses 8 information bits, 2 start bits, 1 stop bit and 1 parity bit for each character. A synchronous transmission T2 uses 3 eight bit sync characters followed by 30 eight bit information characters. If the bit rate is 1200 bits/second in both cases, what are the transfer rates of Ti and T2?

1. 100 characters/sec, 153 characters/sec
2. 80 characters/sec, 136 characters/sec
3. 100 characters/sec, 136 characters/sec
4. 80 characters/sec, 153 characters/sec

✅ Correct Answer: 3

In a sliding window ARQ scheme, the transmitter's window size is N and the receiver's window size is M. The minimum number of distinct sequence numbers required to ensure correct operation of the ARQ scheme is

1. min (M, N)
2. max (M, N)
3. M + N
4. MN

✅ Correct Answer: 3

Which one of the following protocols is NOT used to resolve one form of address to another one?

1. DNS
2. ARP
3. DHCP
4. RARP

✅ Correct Answer: 3

Identify the correct sequence in which the following packets are transmitted on the network by a host when a browser requests a webpage from a remote server, assuming that the host has just been restarted.

1. HTTP GET request, DNS query, TCP SYN
2. DNS query, HTTP GET request, TCP SYN
3. DNS query, TCP SYN, HTTP GET request
4. TCP SYN, DNS query, HTTP GET request

✅ Correct Answer: 3

A firewall is to be configured to allow hosts in a private network to freely open TCP connections and send packets on open connections. However, it will only allow external hosts to send packets on existing open TCP connections or connections that are being opened (by internal hosts) but not allow them to open TCP connections to hosts in the private network. To achieve this the minimum capability of the firewall should be that of

1. A combinational circuit
2. A finite automaton
3. A pushdown automaton with one stack
4. A pushdown automaton with two stacks

✅ Correct Answer: 4

Which protocol will be used to automate the IP configuration mechanism which includes IP address, subnet mask, default gateway, and DNS information?

1. SMTP
2. DHCP
3. ARP
4. TCP/IP

✅ Correct Answer: 2

In Go–back 3 flow control protocol every 6th packet is lost. If we have to send 11 packets. How many transmissions will be needed ?

1. 10
2. 17
3. 12
4. 9

✅ Correct Answer: 2

What will be the total minimum bandwidth of the channel required for 7 channels of 400 kHz bandwidth multiplexed together with each guard band of 20 kHz?

1. 2800 khz
2. 2600 khz
3. 3600 khz
4. 2920 khz

✅ Correct Answer: 4

Which of the following is false:

1. Digital signature is used to verify that a message is authentic
2. Digital certificate is issued by a third party
3. Digital certificate ensures integrity of the message
4. Digital signature ensures non-repudiation

✅ Correct Answer: 3

The subnet mask for a particular network is 255.255.31.0. Which of the following pairs of IP addresses could belong to this network?

1. 172.57.88.62 and 172.56.87.233
2. 10.35.28.2 and 10.35.29.4
3. 191.203.31.87 and 191.234.31.88
4. 128.8.129.43 and 128.8.161.55

✅ Correct Answer: 4

Which of the following protocol is called as byte-oriented protocol?

1. Sliding Window Protocol
2. TCP
3. UDP
4. HDLC

✅ Correct Answer: 2

If syn = 0 and ack = 1, it indicates

1. Open connection packet
2. Open connection ack
3. Data packet
4. None of these

✅ Correct Answer: 3

A DNS.....................server gets its data from another DNS server.

1. Primary
2. Secondary
3. Root
4. All of the above

✅ Correct Answer: 2

The .............................field in the MIME header describes the method used to encode the data.

1. Content – type
2. Content – transfer – Encoding
3. Content – ID
4. Content – description

✅ Correct Answer: 2

A client message usually needs ........................ to send mail.

1. SMTP
2. POP
3. Both a and b
4. None of These

✅ Correct Answer: 3

Which one is not a method of HTTP?

1. PATCH
2. OPTION
3. UNLINK
4. CUT

✅ Correct Answer: 4

Which one of the following is a communication protocol used for email?

1. X.400
2. FTAM
3. SNMP
4. EDI

✅ Correct Answer: 1

Which one of the following statement about email is false?

1. Communication takes place at the convenience of both the sender and the receiver
2. Messages can be Include text, graphics audio and video
3. A historical record of messages can be kept
4. Files can be attached to messages

✅ Correct Answer: 1

Which one of the following can be used on the IP network to monitor a router?

1. SNMP
2. SMTP
3. SGCP
4. SNPP

✅ Correct Answer: 1

Which of the following is true?

1. FTP allows systems with different directions structures to transfer files
2. FTP allows a system using ASCII and a system using EBCDIC to transfer files
3. FTP allows a PC and a SUN work station to transfer files
4. None of these

✅ Correct Answer: 4

Which of the following is not a Block cipher?

1. P - box
2. S – box
3. Pandora’s Box
4. Product block

✅ Correct Answer: 3

In a ................................attack, an intruder comes between two communicating parties, Intercepting and replying to their messages.

1. Return
2. man – in – the middle
3. Replay
4. Bucket – bridge

✅ Correct Answer: 2

A computer crime is

1. Any activity in which the thief use the internet
2. An illegal action in which the perpetrator uses special knowledge of computer technology
3. Any crime committed by an AT. Program
4. Any threat to computer or data securi

✅ Correct Answer: 2

In RSA.............................in the common factor in both keys?

1. N
2. e
3. d
4. Mod

✅ Correct Answer: 1

Programs that come into a computer system disguised as something else are called

1. Spoofers
2. Loggers
3. Defacers
4. Trojan horses

✅ Correct Answer: 4

Having a(n) .....................................is important to help large Organization continue operating until Normal computer operations.

1. Firewall
2. Encryption coding process
3. Disaster recovery plan
4. Virus encrypting programs

✅ Correct Answer: 3

In what way does a firewall increase the securities of a VPN?

1. Configured to allow certain ports to access the VPN
2. Physically protects the network from catching fire
3. Restricts the use of specific application software on the network
4. Limits the speed in which transmission of data is carried out

✅ Correct Answer: 3

Choose the false one.

1. Diffie – Hellman protocol is a symmetric key protocol
2. In RSA, both keys are private
3. DES is a block clipher algorithm
4. Vigenere clipher is poly-alphabetic in nature

✅ Correct Answer: 2

There are 15 users communicating to each other. How many pairs of keys are required to authenticate the communications if the symmetric key is used?

1. 15
2. 30
3. 105
4. (15)²

✅ Correct Answer: 3

Let the value of the RTT(Round-Trip-Time)is to be measure (d). The value of the previous RTT be 350μs. Let the value of α be 90% the new RTT, hence the retransmission time is ______ .(Assume it takes a segment at this moment to be acknowledged in 90μs)

1. 396, 796
2. 348, 696
3. 321, 644
4. 324, 648

✅ Correct Answer: 4

Suppose a web server application generates messages consisting of 120 bytes if every second to the Central host, and each message gets encapsulated in a UDP segment and then an IPV4 Datagram. There are no options added in the TCP (or) Ip headers. What percentage of each Datagram will consist of data generated by the application?

1. 81%
2. 75%
3. 25%
4. 20%

✅ Correct Answer: 1

Suppose that a TCP entity receives 2 MB file from the application layer and the IP layer is willing to Carry blocks of maximum size 1600 B; calculate the amount of overhead incurred from Segmenting the file into packet-sized units. Assume both TCP and Ip header of 20 B.

1. 10%
2. 2.6%
3. 2%
4. 17%

✅ Correct Answer: 2