2.3 Packet Encapsulation and Lifecycle

Question 1

Packet-switched network

Answer 1

Shared bandwidth on communications links to transport packets between a sender and receiver across a network

Question 2

Open System Interconneciton (OSI) and TCP/IP model

Answer 2

-Clarify the general functions of communication processes
-Reduce complex networking processes into sublayers and components
-Promote interoperability through standard
interfaces
-Enable vendors to change individual features at a single layer rather than rebuilding the entire protocol stack
-Facilitate logical troubleshooting

Question 3

OSI Model

Answer 3

L7- Application
L6- Presentation 
L5- Session
L4- Transport (Segment/ Datagram)
L3- Network (Pocket)
L2- Data Link (Frame)
L1- Physical (Bit)

Question 4

TCP/IP Model

Answer 4

L4- Application
L3- Transport
L2- Internet
L1- Network Access

Question 5

Data Link

Answer 5

Logical Link Control (LLC)- provides an interface for the MAC sublayer.

Media Access Control (MAC)- responsible for framing and performs error control using cyclic redundancy check (CRC).

Question 6

Transport

Answer 6

• Flow control
• Multiplexing
• Virtual circuit management
• Error checking and recovery
• TCP
• UDP
• SCTP

Question 7

Transmission Control Protocol (TCP)

Answer 7

A connection-oriented protocol that provides reliable delivery of data.

Question 8

User Datagram Protocol (UDP)

Answer 8

A connectionless protocol that provides best-effort delivery of data.

Question 9

Stream Control Transmission Protocol (SCTP)

Answer 9

A message-oriented protocol (similar to UDP) that ensures reliable, in-sequence transport with congestion control (similar to TCP).

Question 10

Session

Answer 10

• Network File System (NFS)
• Remote procedure call (PRC), client-server network redirection protocol
• Secure Shell (SSH)
• Session Initiation Protocol (SIP)

Question 11

Presentation

Answer 11

• American Standard Code for Information Interchange (ASCII)
• Extended Binary-Coded Decimal Interchange Code (EBCDIC)
• Graphics Interchange Format (GIC)
• Joint Photographic Experts Group (JPEG)
• Motion Picture Experts Group (MPEG)

Question 12

Application

Answer 12

• File Transfer Protocol (FTP)
• HTTP
• HTTPS
• IMAP
• POP3
• SMTP
• SNMP
• Telnet

Question 13

Data Encapsulation (or data hiding)

Answer 13

Wraps protocol information from the (OSI or TCP/IP) layer immediately above in the data section of the layer below.

Question 14

Protocol Data Unit (PDU)

Answer 14

Describes a unit of data at a particular layer of a protocol.