Concept Exercise Chapter 11 Name:

Date: Class:

Cisco Exercises - Semester 1 - Networking Fundamentals

Chapter 11 Layer 3: Protocols

Introduction

Protocols determine whether data is passed beyond the network layer to higher levels of the OSI model. Basically, for this to occur, the data packet must contain both a destination MAC address and a destination IP address. If it lacks one or the other, the data will not be passed to the upper levels. In this way, MAC addresses and IP addresses act as a sort of check and balance for each other.

Concept Questions

Demonstrate your knowledge of these concepts by answering the following questions in the space provided.

• If the destination is to retain the data and pass it along to the higher layers of the OSI model, the source must use both a destination MAC address and a destination IP address. Therefore, the device initiates a process called an Address Resolution Protocol (ARP) request that is designed to help it discover what the destination MAC address is. How does the device know to initiate the ARP request?

• The protocol that a device uses when it does not known its own IP address is the Reverse Address Resolution Protocol (RARP). Like ARP, RARP binds MAC addresses to IP addresses so that network devices can use them to encapsulate data before sending it out on the network. Can you explain how this works?

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