Cn Quiz-4 [IT-b]

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.

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.

The given correct answer is "All the above". This means that all three statements mentioned in the question regarding User Datagram Protocol (UDP) are true. UDP does have a fixed-sized header, it is unreliable (as it does not guarantee delivery or ordering of packets), and the checksum in UDP is optional (it is not mandatory for every packet to have a checksum).

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.

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.

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.

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.

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.

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.

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.