Chapter 2: The TCP/IP & OSI Networking Models

Question 1

Data Encapsulation

Answer 1

The process of adding headers and sometimes trailers around some data for transport.

Question 2

List the OSI Model Layers in Order (7 - 1)

Answer 2

Application
Presentation
Session
Transport
Network
Data Link
Physical

Question 3

List the Original TCP/IP Model Layers in Order (4 - 1)

Answer 3

Application
Transport
Internetwork
Network Access

Question 4

List the Updated TCP/IP Model Layers In Order (5 - 1)

Answer 4

Application
Transport
Internetwork
Data Link
Physical

Question 5

OSI Layer 7 - Name & Function

Answer 5

APPLICATION
~Provides an interface between communications software and any applications that need to communicate outside the computer on which the application resides.
~Defines processes for user authentication

Question 6

OSI Layer 6 - Name & Function

Answer 6

PRESENTATION
~To define & negotiate data formats such as ASCII & EBCDIC text, binary, BCD, & JPEG.
~Provides Encryption Services as well.

Question 7

OSI Layer 5 - Name & Function

Answer 7

SESSION
~Establishes & maintains end-to end bidirectional flows b/w endpoints.
~Includes managing transactions flows.

Question 8

OSI Layer 4 - Name & Function

Answer 8

TRANSPORT
~Provides a variety of services b/w two host computers, including
~Connection Establishments & Termination
~Flow Control
~Error Recovery
~Segmentation of large data blocks into smaller parts for transmission

Question 9

OSI Layer 3 - Name & Function

Answer 9

NETWORK
~Logical Addressing
~Routing
~Path Determination

Question 10

OSI Layer 2 - Name & Function

Answer 10

DATA LINK
~Formats data into frames appropriate for transmission into some physical medium.
~Defines rules for when the medium can be used.
~Defines means in which to recognize transmission errors.

Question 11

OSI Layer 1 - Name & Function

Answer 11

PHYSICAL
~Defines electrical, optical, cabling & procedural details required for transmitting bits, represented as some form of energy passing over a physical medium.

Question 12

Adjacent Layer Interaction

Answer 12

The concept of how two networking model layers, on the same computer, work together.

Question 13

Same-Layer Interaction

Answer 13

When a particular layer on one computer wants to communicate with the same layer on another computer.

Question 14

Decapsulation

Answer 14

On a computer that receives data over the network, the process in which the device interprets the lower layer headers & when finished w/ each header, removes the header, reveals the next higher level PDU.

Question 15

Frame

Answer 15

The term for headers, possible trailers, and the encapsulated data at the Network Access Layer.
*OSI Model Refers to a Frame as a L2PDU.

Question 16

Networking Model

Answer 16

Refers to a comprehensive set of documents. Individually, each document describes one small function required for a network; collectively, these documents define everything that should happen for a computer network to work.
*Some documents define a protocol, others define some physical requirements for networking.

Question 17

Protocol

Answer 17

A set of logical rules that devices must follow to communicate.

Question 18

Packet

Answer 18

The term for headers & the encapsulated data at the Internet Layer.
*OSI Model Refers to a Packet as a L3PDU.

Question 19

Segment

Answer 19

The term for headers & the encapsulated data at the Transport Layer.
*OSI Model Refers to a Segment as a L4PDU.

Question 20

PDU

Answer 20

Protocol Data Unit

• OSI Model term that represents the bits that include the headers, trailers & encapsulated data for that particular layer.
• TCP/IP refer to PDU’s as Segments, Packets, & Frames

Question 21

Example Protocols for: Application, Presentation, & Session Layers (5-7)

Answer 21

Telnet, HTTP, FTP, SMTP, POP3, VoIP, SNMP

Question 22

Example Protocols for: Transport Layer (4)

Answer 22

TCP & UDP

Question 23

Example Protocols for: Network Layer (3)

Answer 23

IP

Question 24

Example Protocols for: Data Link Layer (2)

Answer 24

Ethernet (IEEE 802.3), HDLC, Frame Relay, PPP

Question 25

Example Protocols for: Physical Layer (1)

Answer 25

RJ-45, EIA/TIA-232, V.35, Ethernet (IEEE 802.3)

Question 26

Example Devices for: Application, Presentation, & Session Layers (5-7)

Answer 26

Firewall, Intrusion Detection Systems, Hosts

Question 27

Example Devices for: Transport Layer (4)

Answer 27

Hosts, Firewalls

Question 28

Example Devices for: Network Layer (3)

Answer 28

Router

Question 29

Example Devices for: Data Link Layer (2)

Answer 29

LAN Switch, Wireless Access Point, Cable Modem, DSL Modem

Question 30

Example Devices for: Physical Layer (1)

Answer 30

LAN Hub, LAN Repeater, Cables