CS6250 COMPUTER NETWORKS FINAL
ASSESSMENT TEST PAPER 2026 EXTENSIVE
QUESTIONS AND PRECISE VERIFIED
SOLUTIONS GUARANTEED A+
⩥ What is a packet for the transport layer called? Answer: WA segment.
(If it is a TCP packet)
Datagram (If it is UDP packet)
⩥ TCP packet name. Answer: WA Segment
⩥ UDP packet name. Answer: Datagram
⩥ Transport Layer Protocols. Answer: - User datagram protocol (UDP)
- Transmission Control Protocol (TCP).
⩥ Multiplexing. Answer: Multiplexing is the ability for a host to run
multiple applications using the network simultaneously.
It's necessary to ensure multi-tasking with the host.
,Multiplexing essentially combines multiple signals into one with 1 IP
and multiple ports, where each application binds itself to a port.
Allow multiple apps to communicate to different servers with 1 IP
address
⩥ Describe the two types of multiplexing/demultiplexing.. Answer: 1.
Connectionless Multiplexing/Demultiplexing: Uses the UDP socket that
consists of a two-tuple made up of a destination IP address and port.
Transport layer identifies port from receiverd datagram that includes the
port.
2. Connection Oriented Multiplexing/Demultiplexing: Uses the TCP
socket and is a four-tuple that consists of IP address, source port,
destination IP address, destination port.
⩥ What are the differences between UDP and TCP?. Answer: UDP is
A.) unreliable protocol lacks mechanisms that TCP has in place.
B.) a connectionless protocol doesnt require establishment of
connection (exe: three way handshake) before sending packets.
Benefits to UDP
,A.) no congestion control or similar mechanism.
B.) No connection management overhead.
The UDP packet structure is 64bit header consisting:
1.) Source and destination ports.
2.) Length of UDP segment (header and data).
3.) Checksum (error checking mechanism).
Since no guarantee for link-by-link reliability, need basis mechanism for
error checking.
TCP is protocol consisting of three-way handshake and onnection
teardown:
3-way Handshake:
Step 1: CP client sends special segment, (containing no data) and with
SYN bit set to 1. Client also generates initial sequence number
(client_isn) and includes in this special TCP SYN segment.
, Step 2: Server upon receiving this packet, allocates required resources
for connection and sends back special 'connection-granted' segment
which we call
⩥ UDP Error Checking. Answer: Since no guarantee for link-by-link
reliability, need basis mechanism for error checking.
UDP sender adds the src port, dest port and packet length.
Then takes sum and performs 1s complement (all 0s turned to 1 and all
1s turned to 0s).
If during sum there is overflow, it's wrapped around.
The receiver adds all four 16-bit words (including checksum). Result
should be all 1s unless error occurred.
To detect errors, receiver adds four words (three original words and
checksum).
If sum contains zero, receiver knows has been an error.
ASSESSMENT TEST PAPER 2026 EXTENSIVE
QUESTIONS AND PRECISE VERIFIED
SOLUTIONS GUARANTEED A+
⩥ What is a packet for the transport layer called? Answer: WA segment.
(If it is a TCP packet)
Datagram (If it is UDP packet)
⩥ TCP packet name. Answer: WA Segment
⩥ UDP packet name. Answer: Datagram
⩥ Transport Layer Protocols. Answer: - User datagram protocol (UDP)
- Transmission Control Protocol (TCP).
⩥ Multiplexing. Answer: Multiplexing is the ability for a host to run
multiple applications using the network simultaneously.
It's necessary to ensure multi-tasking with the host.
,Multiplexing essentially combines multiple signals into one with 1 IP
and multiple ports, where each application binds itself to a port.
Allow multiple apps to communicate to different servers with 1 IP
address
⩥ Describe the two types of multiplexing/demultiplexing.. Answer: 1.
Connectionless Multiplexing/Demultiplexing: Uses the UDP socket that
consists of a two-tuple made up of a destination IP address and port.
Transport layer identifies port from receiverd datagram that includes the
port.
2. Connection Oriented Multiplexing/Demultiplexing: Uses the TCP
socket and is a four-tuple that consists of IP address, source port,
destination IP address, destination port.
⩥ What are the differences between UDP and TCP?. Answer: UDP is
A.) unreliable protocol lacks mechanisms that TCP has in place.
B.) a connectionless protocol doesnt require establishment of
connection (exe: three way handshake) before sending packets.
Benefits to UDP
,A.) no congestion control or similar mechanism.
B.) No connection management overhead.
The UDP packet structure is 64bit header consisting:
1.) Source and destination ports.
2.) Length of UDP segment (header and data).
3.) Checksum (error checking mechanism).
Since no guarantee for link-by-link reliability, need basis mechanism for
error checking.
TCP is protocol consisting of three-way handshake and onnection
teardown:
3-way Handshake:
Step 1: CP client sends special segment, (containing no data) and with
SYN bit set to 1. Client also generates initial sequence number
(client_isn) and includes in this special TCP SYN segment.
, Step 2: Server upon receiving this packet, allocates required resources
for connection and sends back special 'connection-granted' segment
which we call
⩥ UDP Error Checking. Answer: Since no guarantee for link-by-link
reliability, need basis mechanism for error checking.
UDP sender adds the src port, dest port and packet length.
Then takes sum and performs 1s complement (all 0s turned to 1 and all
1s turned to 0s).
If during sum there is overflow, it's wrapped around.
The receiver adds all four 16-bit words (including checksum). Result
should be all 1s unless error occurred.
To detect errors, receiver adds four words (three original words and
checksum).
If sum contains zero, receiver knows has been an error.
