CN Quiz-4 [IT-B]

2.

The process on a host is identified by

Sequence Number
Process ID
Port Number
Host Name

Correct Answer

A. Port Number

Explanation

The process on a host is identified by its port number. A port number is a 16-bit number that is used to uniquely identify a specific process or service running on a host. It allows multiple processes to run simultaneously on a host and ensures that the data packets are delivered to the correct process. By using different port numbers, multiple applications can communicate with the network at the same time without conflicts.

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3.

The authority to assign and control well known ports is

IANA
ISP
ICANN
IETF

Correct Answer

A. ICANN

Explanation

ICANN stands for Internet Corporation for Assigned Names and Numbers. It is a non-profit organization that has the authority to assign and control well-known ports. ICANN is responsible for managing the domain name system (DNS) and coordinating the allocation of IP addresses. It ensures that the internet functions smoothly and effectively by overseeing the assignment of unique identifiers and protocols.

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4.

In Go-Back-N protocol, if receiver get an error-free packet with sequence number not equal to R_n then it

Accepts the received packet and sends an ACK with acknowledgment number = R_n
Just accepts the received packet
Discards the received packet and sends an ACK with acknowledgment number = R_n
None of the above

Correct Answer

A. Discards the received packet and sends an ACK with acknowledgment number = R_n

Explanation

In the Go-Back-N protocol, if the receiver receives a packet with a sequence number not equal to Rn, it means that the packet is out of order. In this case, the receiver discards the received packet because it is not the expected packet. However, the receiver still needs to send an acknowledgment to the sender to inform it about the expected sequence number. Therefore, the receiver sends an ACK with acknowledgment number = Rn to indicate that it is expecting the next packet with sequence number Rn.

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5.

Read the following statements: (a) The port numbers ranging from 0 to 1,023 are assigned and controlled by ICANN. (b) Dynamic ports cannot be used as private port numbers (c) The port numbers ranging from 1024 to 49,151 are not controlled by ICANN. (d) Universal port numbers for servers are called well-known ports. Which of these statements are not correct?

(a) and (c)
(c) and (d)
(b) only
None of the above

Correct Answer

A. (b) only

Explanation

Statement (b) states that dynamic ports cannot be used as private port numbers. This statement is incorrect because dynamic ports can be used as private port numbers. Dynamic ports are typically used by client applications to establish connections with server applications, and they are assigned by the operating system from a range of available port numbers. These dynamic ports can be used as private port numbers for communication within a private network. Therefore, the correct answer is (b) only.

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6.

In stop and wait protocol, if expected packet reaches at the receiver but is erroneous then

Receiver simply discards the packet
Receiver send NACK to sender
Receiver detects and corrects the error
Receiver sends ACK

Correct Answer

A. Receiver simply discards the packet

Explanation

In the stop and wait protocol, if the expected packet reaches the receiver but is erroneous, the receiver simply discards the packet. This is because in the stop and wait protocol, the receiver expects a specific packet and if it is found to be erroneous, it is considered invalid and therefore discarded. The receiver does not send a NACK (negative acknowledgement) to the sender or attempt to correct the error. The correct packet will be retransmitted by the sender in this protocol.

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7.

In stop and wait protocol, maximum size of the send window is

2^m-1
1
2
2^m

Correct Answer

A. 1

Explanation

In stop and wait protocol, the maximum size of the send window is 1. This means that the sender can only send one packet at a time and must wait for an acknowledgment before sending the next packet. This protocol ensures reliable delivery of packets as it allows for error detection and retransmission if necessary. The limited window size prevents congestion and ensures that the receiver can handle the incoming packets effectively.

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8.

In UDP, checksum is computed over

Entire UDP segment
Only on UDP header and Data Coming from Application Layer
Pseudo Header, UDP Header and Data Coming from Application Layer
Pseudo Header plus UDP header

Correct Answer

A. Pseudo Header, UDP Header and Data Coming from Application Layer

Explanation

The correct answer is "Pseudo Header, UDP Header and Data Coming from Application Layer". In UDP, the checksum is computed over the pseudo header, which includes the source and destination IP addresses, protocol number, and UDP length. It is also computed over the UDP header, which includes the source and destination port numbers, length, and checksum field itself. Finally, the checksum is computed over the data coming from the application layer, which is the actual payload of the UDP segment. This comprehensive checksum calculation ensures the integrity of the entire UDP segment.

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9.

Out-of-order delivery can be handled by

Stop-and-wait protocol
Go-Back-N Protocol
Simple Protocol
Selective Repeat Protocol

Correct Answer

A. Selective Repeat Protocol

Explanation

Selective Repeat Protocol is able to handle out-of-order delivery. In this protocol, the sender sends multiple packets before receiving an acknowledgment from the receiver. The receiver has a buffer to store the out-of-order packets and can reorder them before delivering them to the upper layer. This allows for efficient utilization of the network and reduces the delay caused by retransmissions. Additionally, Selective Repeat Protocol also provides error detection and retransmission of lost packets, making it a reliable choice for handling out-of-order delivery.

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10.

If a TCP connection is transferring a file of 1000 bytes. The first byte is numbered 10001. What is the sequence number of the segment if all data is sent in only one segment

10000
10001
11001
12001

Correct Answer

A. 10001

Explanation

The sequence number of the segment would be 10001. This is because the first byte is numbered 10001, and since all data is sent in only one segment, the sequence number of the segment would be the same as the sequence number of the first byte.

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Cn Quiz-4 [IT-b]

Regarding User Datagram Potocol (UDP), following is true

Quiz Preview

The process on a host is identified by

The authority to assign and control well known ports is

In Go-Back-N protocol, if receiver get an error-free packet with sequence number not equal to R_n then it

In stop and wait protocol, if expected packet reaches at the receiver but is erroneous then

In stop and wait protocol, maximum size of the send window is

In UDP, checksum is computed over

Out-of-order delivery can be handled by

If a TCP connection is transferring a file of 1000 bytes. The first byte is numbered 10001. What is the sequence number of the segment if all data is sent in only one segment

Cn Quiz-4 [IT-b]

Regarding User Datagram Potocol (UDP), following is true

Quiz Preview

The process on a host is identified by

The authority to assign and control well known ports is

In Go-Back-N protocol, if receiver get an error-free packet with sequence number not equal to Rn then it

In stop and wait protocol, if expected packet reaches at the receiver but is erroneous then

In stop and wait protocol, maximum size of the send window is

In UDP, checksum is computed over

Out-of-order delivery can be handled by

If a TCP connection is transferring a file of 1000 bytes. The first byte is numbered 10001. What is the sequence number of the segment if all data is sent in only one segment

In Go-Back-N protocol, if receiver get an error-free packet with sequence number not equal to R_n then it