Network Wiring

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					INFO 341 Computer Networks and Distributed Applications

Lab 1 – Network Wiring & Device Connection

What to bring for the assignment

You need to bring a blank writeable CD.


Group work: You will team up with your classmates for this lab. You should work with the same
team for the entire lab (it is OK to switch your lab partners for the upcoming labs). You and your
team only need to submit a single write-up for this lab. Groups are limited to four students.

These are not cookbook, step-by-step, or follow-along labs. Rather, you are given directions for
what must be accomplished, not exactly how. Part of learning IT is figuring out the "how" part. Be
sure to document any extra steps that you needed to take to obtain your results. Be sure you
answer all of the questions in the lab.

Final Deliverable:

1) Please detail all the steps (e.g.: commands you used)
2) Take some screen-shots (feel free to use your favorite screen shot tools or
simply take a picture with your camera) to reflect your progress.
3) Include a reference section and individual contribution/responsibility
4) A brief section of challenge you encounter & how you solved


Note: You are not limited to use KNOPPIX, we just happened to choose it as an example. You are free to use
any Linux distribution, for more information about the available Linux distributions, please visit: . No matter which Linux distribution you choose, you will have to finish this lab manually
(some distributions do everything for you automatically, you will receive no credit if your report doesn't

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show us your understanding and progress).

We will use KNOPPIX_V5.1.1CD-2007-01-04-EN.iso of the Knoppix Linux live CD distribution
downloadable from mirrors listed here:

We‟re not using Windows Vista because it‟s configured in such a way that the networking breaks if
you take the computer off the university LAN. The other problem is that Windows Vista generates
network traffic periodically by looking for other windows machines and talking to the iSchool
domain. That would get in the way with this lab, where you only want traffic when you‟ve explicitly
asked for it.

Using Linux should be pretty straightforward, for the purposes of this lab at least. Burn the ISO
image to blank 700 Megabyte CDROM (bring your own blanks). From the Knoppix folder, you only
need to burn one ISO image. Download the latest English version. Once your CD is burnt
successfully, reboot your computer from the CD (check that your CD is in the correct disk drive). It
will boot up to a GUI, from which you launch a terminal window that is what you use to interact with
Linux. To see the network configuration (including the MAC address of the machine‟s NIC), use
“ifconfig”. Each system should be configured with a different IP address (IP addresses will be
discussed later, so don‟t worry about it for now.) You refer to the machines by using the IP address.
To ping a specific a specific computer, use “ping”, substituting the IP address of the
computer you want to talk to. To ping every computer on your network, use the broadcast IP
address: “ping”. Unlike Windows ping, Linux ping will keep going forever until you press

Ping is an extremely simple network application that sends a single packet to a remote computer‟s
“echo port” every second. All an echo port does is send back whatever data it receives, so as soon
as the remote computer gets the ping packet, it builds a new packet, fills it with the data from the
packet it just received, and sends it back to the original computer. When the original computer
receives the reply packet, it displays the total round trip time in milliseconds. Ping is an excellent
way to determine network connectivity and network latency (the time it takes for packets to traverse
the network), which is exactly what you‟ll be using it for in this lab.

Part A – Straight-Through and Crossover Cable Construction

    1. Build a straight-through and a crossover Ethernet cable. The following instructions will help
       you complete this task. {Part A is based on a lab exercise from, which
       provides fee-based network training.} When you have a working cable, validate that your
       cable works by having somebody else in the group test it independently. Please re-use
       cable from the recycling box whenever possible (we have limited cable). Cut off connectors
       to create your own. When done with the whole lab, leave cables in the appropriate recycling

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        box for re-use.

The components needed for this exercise include:

       Category 5 cable

       RJ-45 connectors and guides

       A stripper/crimper

       Cable tester (product manual here)

Figure 1--multipurpose crimper, cutter, stripper

    1. Measure off about 3 feet of CAT5 cable.

    2. Strip 3/4 inch of the outer jacket from the cable using the cable stripper.

    3. Untwist and align the eight leads as shown in Diagram 1, the RJ45 diagram.

    4. Trim all eight leads to a length of 1/2 inch by simultaneously clipping the wires with the wire

    5. Keeping the leads aligned, insert them into the RJ45 connector and press the cable into the
       connector until the metal wire ends are all visible through the end of the connector. We
       purchased a brand of connector, which requires that you insert the cable into a cable guide
       and then the cable guide (with the cable inserted) into the RJ-45 plug (See instructions in
       Fig. 2).

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                Figure 2--Instructions on how to insert the wires into the RJ-45 connector

   6. Insert the RJ45 connector, with the cable inserted, into the cable/connector crimper.

   7. While pressing on the cable, inspect the end of the connector to make sure the metal wire
      leads can all be seen pressed against the end of the connector. If all of the wire ends are
      pressed against the end of the connector, squeeze the handles of the crimper as far as they
      will go and hold them for approximately 3 or 4 seconds.

   8. Remove the RJ45 cable assembly from the crimper and inspect the connector to make sure
      the wires are all aligned properly.

   9. Using the same procedure as you used to connect the first connector, attach another RJ45
      connector to the other end of the cable to complete construction of a straight-through
      (T568B/T568B) cable. {Note: Both ends of the cable should look like the T568B RJ45
      Configuration diagram shown below.}

   10.       Plug both ends of the cable into the cable tester(s) and check to make sure that the
     cable is good by pressing the „mode‟ button until „wiremap‟ appears. A good straight cable
     should read 12345678 - 12345678, a crossover cable 12345678 - 36145278. If the cable
     tester indicates a bad cable, clip the RJ45 connector off of one of the ends of the cable
     (choose the one that is most questionable first) and then attach a new connector on to the

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      exposed end of the cable and retest. If the rebuilt cable fails the test, clip off the other
      connector (that hadn‟t already been replaced) and install a new RJ45 connector on that end
      of the cable and then retest.

    11.      Use these same basic instructions to make a crossover cable.

Diagram 1: RJ45 diagram

Hook Is On Top Hook Is Underneath

                                    Straight-through Cable (T568B/T568B)

                                         RJ45 Connector (T568B)

                                         Pin Wire Color Signal

                                         1 White/Orange Transmit -

                                         2 Orange Transmit +

                                         3 White/Green Receive -

                                         4 Blue

            5 White/Blue

            6 Green Receive +

            7 White/Brown

            8 Brown

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Hook Is On Top Hook Is Underneath

                                    Crossover Cable (T568A/T568B)

RJ45 Connector (T568B) RJ54 Connector (T568A)

Pin Wire Color Pin Wire Color

1 White/Orange 1 White/Green

2 Orange 2 Green

3 White/Green 3 White/Orange

4 Blue 4 Blue

5 White/Blue 5 White/Blue

6 Green 6 Orange

7 White/Brown 7 White/Brown

8 Brown 8 Brown

    2. Burn a Knoppix Linux Live CDROM for each computer. Boot two computers with the Linux
       CDs and connect them together using the straight-through cable. See if the link lights (green
       lights on the NIC) come on, and if so, see if you can send data between them with the ping
       command. Then replace the cable with a crossover cable. Record your observations for both
       cables and write a brief explanation.

    3. Get another straight-through cable and use both straight-through cables to connect two

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       computers to a hub (one of the NetGear DS104 hubs). Does this configuration allow data to
       be sent between the computers? Record your observations and write a brief explanation.

    4. Use your crossover cable to add a third computer to the hub. Can you find a combination of
       cables and ports that works? Record your observations and write a brief explanation.

Part B – 10/100Mbit Transmission Speed Calculation

For this part you need a 10Mbit hub, a 10/100Mbit hub, four straight-through cables, and three
computers. Connect two computers to the 10/100Mbit hub and the third computer to the 10Mbit
hub. Then connect the two hubs. What you have now is two network segments running at different
speeds being internally bridged by the 10/100 hub.

    1. Estimate the data transmission speed on your network and find out how many Mbits/second
       you are getting between each of the three computers. Hint: ping has an option that allows
       you to specify the amount of data it sends. To send a 10kilobyte packet, use “ping -s 10000
       ip_address”. Draw a diagram of this small network configuration. Write the general formula
       for estimating transmission speed on this network. In a table indicate the estimated
       transmission speed between each of the computers on this small network.

Part C – Hub versus Switch Behavior

For this part you need a switch (Intel 520T switch), a 10/100Mbit hub, a 10Mbit hub, at least three
computers, and enough cables to connect them. The problem is to determine how each of the
three devices (10Mbit hub, 10/100Mbit hub and switch) handles data on the network. Experiment
with each device; plug three computers into one of the devices and send some ping packets. Make
sure to ping specific computers and the broadcast address. Watch the lights on the device and the
activity lights on the NICs in the computers carefully to determine where data is being sent. Hint:
you will get a brighter blink from an activity light if you send big packets using the “-s” option as in
Part B.

    1. Connect three computers to the 10Mbit hub. Experiment with various directed pings (pings
       to specific machines on your small network) and with pings to the broadcast address.
       Record your observations. Does the 10Mbit hub pass all directed pings and broadcast pings
       to each of its ports?
    2. Connect three computers to the 10/100Mbit hub. Experiment with various directed pings
       (pings to specific machines on your small network) and with pings to the broadcast address.
       Record your observations. Does the 10/100Mbit hub pass all directed pings and broadcast

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      pings to each of its ports?
    3. Connect three computers to the small switch. Experiment with various directed pings (pings
       to specific machines on your small network) and with pings to the broadcast address.
       Record your observations. Does the switch pass all directed pings and broadcast pings to
       each of its ports?

Part D – Switch Inner Workings

We have five Intel Express 520T/550T (or whatever switches that are available to you) switches
available for Part D. These switches are quite a bit more complex and capable than the hubs and
switch you used in Parts B and C, but they still do the same basic thing when it comes to switching
traffic. For this part you will need at least three computers, one Intel Express 520T switch and
enough cables to connect them.

Being intelligent switches, you'll need to configure their IP addresses. The switches may already be
configured and labeled with an IP address, in which case you can proceed with the lab. Otherwise
you should search for and download the switch management software and manuals from the Intel
web site. You'll need a PC running Windows Vista to install the Intel switch management software.
Use the software to configure the switch IP parameters. Label the switches accordingly for the next
group of students.

    1. Plug your computers into the switch
    2. Type “telnet ip_address” from a command prompt to open the switch console (you only need
       to do this from one computer), replacing ip_address with the actual IP address of the switch.
       Pick the administrator option and just hit enter when it asks for a password. Select
       “Monitoring” and then select “Filter Info”. This shows you what MAC address the switch has
       seen on each port (you can ignore the Mgt. port).
    3. Experiment with the ping command and by moving computers to different ports on the
       switch, figure out how the table changes. Try starting a ping and then moving the source
       and/or destination computers to different ports while ping is running. Record your
       observations and write a paragraph describing how the switch maintains its MAC address
    4. Hit escape to leave the MAC address table and select “Switch Info”. You should see stats
       such as total packets sent/received and the current network speed in bytes/sec. After
       stopping any ping programs still running, you will see that the network traffic remains at
       around 500bytes/sec instead of dropping to zero. Why is there still traffic on the network?

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