CS6250 COMPUTER NETWORK EXAM 2 |
Complete Study Guide with Questions and
Verified Answers | 100% Correct | Graded
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‣ Network Layer -✓✓logical communication between hosts
‣ Transport Layer -✓✓logical communication between processes
• relies on, enhances, network layer services
‣ Transport Layer Actions: Sender -✓✓§ is passed an application-layer
message
§ determines segment header fields values
§ creates segment
§ passes segment to IP
‣ Transport Layer Actions: Receiver -✓✓§ receives segment from IP
§ checks header values
§ extracts application-layer message
§ demultiplexes message up to application via socket
‣ TCP: Transmission Control Protocol -✓✓• reliable, in-order delivery
,• congestion control
• flow control
• connection setup
‣ UDP: User Datagram Protocol -✓✓• 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 -✓✓
‣ How demultiplexing works -✓✓
‣ Connectionless demultiplexing -✓✓
, ‣ Connectionless demultiplexing: example -✓✓
‣ Connection-oriented demultiplexing -✓✓§ 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? -✓✓- 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
Complete Study Guide with Questions and
Verified Answers | 100% Correct | Graded
A+
‣ Network Layer -✓✓logical communication between hosts
‣ Transport Layer -✓✓logical communication between processes
• relies on, enhances, network layer services
‣ Transport Layer Actions: Sender -✓✓§ is passed an application-layer
message
§ determines segment header fields values
§ creates segment
§ passes segment to IP
‣ Transport Layer Actions: Receiver -✓✓§ receives segment from IP
§ checks header values
§ extracts application-layer message
§ demultiplexes message up to application via socket
‣ TCP: Transmission Control Protocol -✓✓• reliable, in-order delivery
,• congestion control
• flow control
• connection setup
‣ UDP: User Datagram Protocol -✓✓• 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 -✓✓
‣ How demultiplexing works -✓✓
‣ Connectionless demultiplexing -✓✓
, ‣ Connectionless demultiplexing: example -✓✓
‣ Connection-oriented demultiplexing -✓✓§ 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? -✓✓- 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
