Lab 2.3.4 OSI Model and TCP/IP - Overview

Estimated time: 20 min.

Objectives:

This Lab will focus on your ability to accomplish the following tasks:

·  Describe the 4 layers of the TCP/IP model

·  Relate the seven layers of the OSI model to the 4 layers of the TCP/IP model

·  Name the primary TCP/IP protocols and utilities that operate at each layer

Background:

This lab will help you develop a better understanding of the seven layers of the OSI model as they relate to the most popular functioning networking model in existence, the TCP/IP model. The Internet is based on TCP/IP which has become the standard language of networking. Although the TCP/IP model is the most widely used, the 7 layers of the OSI model are the ones most commonly used to describe and compare networking software and hardware from various vendors. It is very important to know both the OSI and TCP/IP models and be able to relate (or map) the layers of one to the other. An understanding of the TCP/IP model and the protocols and utilities that operate at each layer is essential when troubleshooting.

Tools / Preparation:

You may work individually or in teams. The following resources will be required:

·  PC workstation with Monitor, keyboard, mouse, and power cords

·  Windows operating system (Win 95, 98, NT or 2000) installed on PC

·  NIC installed and Cat 5 patch cable with connection to the Internet

·  Browser software installed (Netscape Navigator 4.6.1 or higher or Internet Explorer 5.1 or higher

·  Java, JavaScript, and Style Sheets (must be enabled in your browser's preference settings)

·  Flash plug-in (Curriculum version 2.1 only)

·  Apple QuickTime, RealPlayer G2 and ShockWave Macromedia browser plug-ins (Curriculum version 1 and 2 only)

·  Sample Ethernet and Token Ring NICs with different connectors (Coax, AUI, RJ-45)

·  Sample Hubs, Switches and Routers

Notes:

Step 1 – The OSI model and associated TCP/IP protocol stack layer.

Task: Fill out the following charts based on your knowledge of the OSI model and TCP/IP models.
Explanation: Your understanding of the OSI model as it relates to the TCP/IP model will greatly increase your ability to absorb and categorize networking information as you learn it.

1. List the 7 layers of the OSI model from the top to the bottom with the proper name for each layer. List the TCP/IP layer number and its correct name in the next columns. Also list the term used for the encapsulation units, the related TCP/IP protocols / utilities and the devices that operate at each layer. NOTE: More than one OSI layer will be related to certain TCP/IP layers.

OSI comparison with TCP/IP Protocol Stack

OSI # / OSI Layer Name / TCP/IP # / TCP/IP Layer name / Encapsul. Units / TCP/IP Protocols At each TCP/IP layer / TCP Utilities
7
6
5
4
3
2
1

EXERCISE 2.3.4 - OSI MODEL and TCP/IP - ANSWERS

Step 1 - The OSI model and associated TCP/IP protocol stack layer.

Task: Fill out the following chart based on your knowledge of the OSI and TCP/IP models.

Explanation: Your understanding of the OSI model as it relates to the TCP/IP model will greatly increase your ability to absorb and categorize networking information as you learn it.

1.  List the 7 layers of the OSI model from the top to the bottom with the proper name for each layer. List the TCP/IP layer number and its correct name in the next columns. Also list the term used for the encapsulation units, the related TCP/IP protocols / utilities and the devices that operate at each layer. NOTE: More than one OSI layer will be related to certain TCP/IP layers.

OSI comparison with TCP/IP Protocol Stack

OSI # / OSI Layer Name / TCP/ IP # / TCP/IP Layer Name / Encapsul. Units / TCP/IP Protocols At each TCP/IP layer / TCP Utilities
7 / Application / 4 / Application / Data / FTP, HTTP use TCP as transport SMTP, DNS, and TFTP use UDP as transport / Telnet, Rlogin
6 / Presentation / 4 / Application / Data
5 / Session / 4 / Application / Data
4 / Transport / 3 / Transport / Segments / TCP or UDP
3 / Network / 2 / Internet / Packets (datagrams) / IP, ICMP, ARP, RARP / Ping, Traceroute
2 / Data Link (LLC & MAC) / 1 / Network (interface) / Frames
1 / Physical / 1 / Network (interface) / Bits