CS6250 COMPUTER NETWORK EXAM 2
QUESTIONS WITH VERIFIED ANSWERS 2026 |
Study Guide | A+
• Network Layer. CORRECT ANSWER: logical communication between hosts
• Transport Layer. CORRECT ANSWER: logical communication between processes
• relies on, enhances, network layer services
• Transport Layer Actions: Sender. CORRECT ANSWER: § is passed an application-
layer message
§ determines segment header fields values
§ creates segment
§ passes segment to IP
• Transport Layer Actions: Receiver. CORRECT ANSWER: § receives segment from IP
§ checks header values
§ extracts application-layer message
§ demultiplexes message up to application via socket
• TCP: Transmission Control Protocol. CORRECT ANSWER: • reliable, in-order delivery
• congestion control
• flow control
• connection setup
• UDP: User Datagram Protocol. CORRECT ANSWER: • unreliable, unordered delivery
• no-frills extension of "best-effort" IP
§ "no frills," "bare bones" Internet transport protocol
§ "best effort" service, UDP segments may be:
• lost
• delivered out-of-order to app
§ connectionless:
• no handshaking between UDP sender, receiver
• each UDP segment handled independently of others
• Multiplexing/demultiplexing. CORRECT ANSWER:
• How demultiplexing works. CORRECT ANSWER:
• Connectionless demultiplexing. CORRECT ANSWER:
, • Connectionless demultiplexing: example. CORRECT ANSWER:
• Connection-oriented demultiplexing. CORRECT ANSWER: § TCP socket identified by
4-tuple:
• source IP address
• source port number
• dest IP address
• dest port number
§ server may support many simultaneous TCP sockets:
• each socket identified by its own 4-tuple
• each socket associated with a different connecting client
§ demux: receiver uses all four values (4-tuple) to direct segment to appropriate socket
• Why is there a UDP?. CORRECT ANSWER: - No connection establishment (Which
can add to delay)
- Simple: No connection state at sender, receiver
- Small header size
- No congestion control: UDP can blast away as fast as desired
• UDP use. CORRECT ANSWER: - streaming multimedia
apps (loss tolerant, rate
sensitive)
- DNS
- SNMP
-HTTP/3
§ if reliable transfer needed over UDP (e.g., HTTP/3):
- add needed reliability at application layer
- add congestion control at application layer
• UDP sender actions. CORRECT ANSWER: § is passed an application-layer message
§ determines UDP segment header fields values
§ creates UDP segment
§ passes segment to IP
• UDP receiver actions. CORRECT ANSWER: § receives segment from IP
§ checks UDP checksum header value
§ extracts application-layer message
§ demultiplexes message up to application via socket
• UDP segment header. CORRECT ANSWER:
QUESTIONS WITH VERIFIED ANSWERS 2026 |
Study Guide | A+
• Network Layer. CORRECT ANSWER: logical communication between hosts
• Transport Layer. CORRECT ANSWER: logical communication between processes
• relies on, enhances, network layer services
• Transport Layer Actions: Sender. CORRECT ANSWER: § is passed an application-
layer message
§ determines segment header fields values
§ creates segment
§ passes segment to IP
• Transport Layer Actions: Receiver. CORRECT ANSWER: § receives segment from IP
§ checks header values
§ extracts application-layer message
§ demultiplexes message up to application via socket
• TCP: Transmission Control Protocol. CORRECT ANSWER: • reliable, in-order delivery
• congestion control
• flow control
• connection setup
• UDP: User Datagram Protocol. CORRECT ANSWER: • unreliable, unordered delivery
• no-frills extension of "best-effort" IP
§ "no frills," "bare bones" Internet transport protocol
§ "best effort" service, UDP segments may be:
• lost
• delivered out-of-order to app
§ connectionless:
• no handshaking between UDP sender, receiver
• each UDP segment handled independently of others
• Multiplexing/demultiplexing. CORRECT ANSWER:
• How demultiplexing works. CORRECT ANSWER:
• Connectionless demultiplexing. CORRECT ANSWER:
, • Connectionless demultiplexing: example. CORRECT ANSWER:
• Connection-oriented demultiplexing. CORRECT ANSWER: § TCP socket identified by
4-tuple:
• source IP address
• source port number
• dest IP address
• dest port number
§ server may support many simultaneous TCP sockets:
• each socket identified by its own 4-tuple
• each socket associated with a different connecting client
§ demux: receiver uses all four values (4-tuple) to direct segment to appropriate socket
• Why is there a UDP?. CORRECT ANSWER: - No connection establishment (Which
can add to delay)
- Simple: No connection state at sender, receiver
- Small header size
- No congestion control: UDP can blast away as fast as desired
• UDP use. CORRECT ANSWER: - streaming multimedia
apps (loss tolerant, rate
sensitive)
- DNS
- SNMP
-HTTP/3
§ if reliable transfer needed over UDP (e.g., HTTP/3):
- add needed reliability at application layer
- add congestion control at application layer
• UDP sender actions. CORRECT ANSWER: § is passed an application-layer message
§ determines UDP segment header fields values
§ creates UDP segment
§ passes segment to IP
• UDP receiver actions. CORRECT ANSWER: § receives segment from IP
§ checks UDP checksum header value
§ extracts application-layer message
§ demultiplexes message up to application via socket
• UDP segment header. CORRECT ANSWER:
