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Using_Packet_Tracer_Handout

By Sally Butler,2014-04-13 16:09
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Using_Packet_Tracer

Packet Tracer 4.0 Skill Building Activity: Using Packet Tracer

Objective

    Use Packet Tracer to complete the following skills

    ; To learn to use Packet Tracer

    ; To examine Ping and MAC tables on various devices using various methods Scenario

    These topologies represent two networks, one using a hub and the other using a switch.

    These topologies are ideal for studying ARP and ICMP behavior.

    Required Files

    To complete this lab, you will need the following Packet Tracer (.pkt) files.

    ; UsingHub.pkt

    ; UsingSwitch.pkt

    Plan

    To learn to use Packet Tracer.

    What is Packet Tracer? Packet Tracer is a protocol simulator developed by Cisco

    Systems. Packet Tracer (PT) is a powerful and dynamic tool that displays the various

    protocols used in networking, in either Real Time or Simulation mode. This includes

    layer 2 protocols such as Ethernet and PPP, layer 3 protocols such as IP, ICMP, and

    ARP, and layer 4 protocols such as TCP and UDP. Routing protocols can also be traced.

    Purpose: The purpose of this activity is to become familiar with the Packet Tracer

    interface. Learn how to use existing topologies and build your own.

    Act 1 Introduction to the Packet Tracer Interface using a Hub Topology

Step 1 Start Packet Tracer and Entering Simulation Mode

Step 2 Open an existing topology

Perform the following steps to open the UsingHub.pkt file.

    ; Click the Open button on the toolbar.

    ; Open the CCNA1 folder.

    ; Open the SkillBuilder_UsingPacketTracer folder.

    ; Open the file UsingHub.pkt.

By default, the topology opens in Realtime mode. We will examine the difference between

    Realtime and Simulation modes in later steps.

    Simulation mode allows you to view a sequence of events associated with the communications between two or more devices. Realtime mode performs the operation with all of the sequence of events happening at “real time”.

    Help can be obtained by using the Help menu. Both online help and tutorials are available. Please take advantage of these facilities.

    To view the IP address, subnet mask, default gateway, and MAC address of a host, move the cursor over that computer. Be sure the Select tool is selected.

     Select Tool

Step 3 Issue a ping from PC0 to PC1

    Pings and the ICMP protocol will be examined in much more detail in later steps. The ping program generates an IP packet with an encapsulated ICMP Echo Request message. It is a tool used to test basic layer 2 and layer 3 communications between two devices. When the user issues the ping command, most operating systems send multiple (four or five) ICMP Echo messages. When the destination device receives the ping, Echo Request, it issues an Echo Reply.

Command to be issued from PC0 is: ping 192.168.10.37

    Packet Tracer allows you to either issue the command from the command prompt or to use the Add Simple PDU tool. Both methods will be used.

    To enter Simulation Mode click the Simulation Mode tab in the lower right hand corner 0f the interface.

In order to view only the “pings”, in the Event List, click on ALL/NONE

    to clear all protocols, and then click on ICMP to select only that protocol.

Ping: Using the Command Prompt in Realtime Mode

    Return to Realtime mode by clicking the Realtime tab in the lower right hand corner of the screen.

Single click on PC0 with the left mouse button. 2. Click on the Desktop tab. 3. Click on the

    Command Prompt.

Click after PC> prompt and type the following ping command, ping 192.168.10.37 and press the

    Enter key.

Ping: Using the Simulation mode

    Click on the Simulation tab located on the bottom right side of the Packet Tracer screen. The tab is located behind the Realtime mode tab.

If you cannot see the topology close the Event List window.

    Reissue the ping command in the Terminal screen (Use the Up Arrow key to repeat the last command).

You will notice that an ICMP packet is now preparing to leave PC0 (left screen) and is also

    displayed in the Event List (middle screen).

Click on the Capture / Forward button in Play Controls (the yellow bar below the windows) to

    view a step-by-step process of the ping command.

    As you click through the events, notice how the hub processes each frame (Ethernet frame, IP packet, and ICMP message). Notice that each event is listed in the Event List. Also, notice that the ping program displays the ICMP Echo Reply returned to PC0 from PC1.

Continue clicking the Capture / Forward button until all frames have been sent. Notice that the

    hub floods all of the frames out all ports except the port in came in on.

    When the ping program is finished sending four pings (ICMP Echo Requests) you will receive the following message:

Using the Simple PDU Tool

Another method for pinging a device is the use of the Simple PDU tool. This tool performs the

    ping without having to issue the ping command. Before proceeding with this step, close the Desktop for PC0, click the “X” in the right-hand corner.

    Restore the Event List if necessary by clicking Event List on the yellow bar to the left of Simulation and clicking the Reset Simulation button.

Choose the Add Simple PDU tool from the tool box:

    Click once on PC0, the device

    issuing the ping (ICMP Echo

    Request) and then click once on

    PC1 (the destination of the ICMP

    Echo Request).

Click the Capture / Forward button and watch the ICMP Echo Requests and ICMP Echo Replies.

    Notice that the hub floods all of the frames out all ports except the incoming port.

Note: This tool only sends a single ICMP Echo Request instead of the four pings when using the

    command prompt.

Step 4 Viewing the frame using Protocol Analyzer

To examine the actual protocols being sent, click on the colored Info box in the Event List.

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Act 2 Looking at the Switch Algorithm and Switch MAC Address Tables

Step 1

    Open the UsingSwitch.pkt file. Do not save the changes to the current network. Notice the similarity to the previous topology. The layer 1 hub has been replaced with a layer 2 switch.

Click on the Simulation icon to switch to simulation mode.

Step 2 Viewing the Switch MAC Address Table

    Use the Select tool to view IP address and MAC address information for the various hosts.

Use the Inspect tool to view the MAC Address Table of the switch.

     The MAC Address Table is empty as it has not learned any Source Ethernet MAC Addresses. Notice that there is also a VLAN column in this table. This will be discussed in future courses.

Waiting for STP

    Note: Because of how Packet Tracer deals with the Spanning Tree Protocol, at times the switch may show amber lights on its interfaces. To correct this, click the Realtime mode icon, wait for

    the lights to turn green, and then click the Simulation mode icon, returning to where you left off.

Step 3: Issuing a Ping and Viewing the MAC Address Table

Set the Event List Filters to:

    ARP is used to learn the MAC address to use to encapsulate the IP packet in an Ethernet frame. The ARP packet will precede the ICMP packet.

Using the Add Simple PDU perform a ping from PC0 to PC1. Choose the Add Simple PDU tool

    from the toolbox:

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