Introduction to Networking & Network Management

Engineering Science Department

Basics Lab Experiment*

Your Name: Your Station: Your Computer:

You Partners: Date:

A. Objectives1. Understand the wiring of the computer interfaces in the Internet Teaching Lab (ITL)2. Identify the Ethernet & IP addresses of your host station3. Learn how to set an IP address to an interface4. Test connectivity between your computers 5. Observe the effect of cross-over & straight-through cables6. Computer connections by hub & switch7. Learn the effect of congestion at the interface & the link

B. Configuration & Network SetupConfiguring Ethernet ports & connecting computers on a LAN. You may need to login to root using the command sudo –l & the password provided by the instructor.

C. Procedure1. Do steps 1-10 on your own & steps 9 to the end in group of two. Each student needs to submit her/his report for

grading.

2. Consider the wiring diagram of your Work Area as shown in Figure1. We desire to identify various ports & port addresses, modify them as necessary, & connect them physically & logically to communicate.

Figure 1. Wiring Diagram of aWork Area 1 in Networking Lab,

Salazar 2006.

3. Boot the computer & keep tapping on the Upward Arrow key until the display stops & shows a list of OSs (e.g., Ubuntu, Adv. Ubuntu Options, Memory, & Windows 7, ..) on the left top corner of the screen for you to select. Using the Arrow key scroll up to high-light UBUNTU. At this time, hit the Enter key to boot the UBUBTU OS. After a few seconds, the screen prompts you to enter password. Key in the password that the instructor provides you to come to the UBUNTU screen. Note that the screen may timeout periodically in which case you need to enter the password again.

4. As shown in Figure 2 below, each computer has three Ethernet ports (for the Mother board or Ethernet cards) in hardware that you need to connect each Ethernet cable to the proper ports for this experiment.

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The following table lists the three Ethernet ports (eth0, eth1, & eth2) connected to the hardware in the first column, & the three Ethernet cables coming from the production network or the wiring racks. However, we do not know which Ethernet cable should be connected to which hardware (Motherboard, NIC 1, or NIC 2) port.

Three Ethernet ports (eth0, eth1,

eth2) supported by Hardware Board / Network Interface Cards

Three Ethernet cables that connect to various Ethernet ports. The cables may need to connect to different Hardware

Board/Cards.

a. One built-in port on the Mother Board

b. One on NIC 1 (Network Interface Card)

c. One on NIC 2

One cable from the campus connecting to the Production network & to the Internet

A Green cable from Eth1 port on the Patch Panel connecting to the servers at the back of the room

A Grey cable from Eth2 on the Patch Panel that you can connect to the hub, switches, or routers to perform your experiments

To connect each Ethernet cable properly, we need to go through a “trial & error” step. We can identify the first association by the Linux ifconfig command that can display the interfaces, their status (ACTIVE or not), & their ip addresses when they are ACTIVE. Note that before you do the experiment, only the Ethernet cable from the campus (production network) is ACTIVE.

Figure 2. Picture of the back of PC showing the hardware with eth ports for Ethernet cables to connect to.

EthernetJack view

Ports HardwareConnect colored Ethernet cable to

hardware with proper eth port

Eth0 Production = eth0

Eth1 Green = eth1

Eth2 Grey = eth2

So, open a Terminal display & enter ifconfig. The computer will display the eth ports (eth0, eth1, or eth2) & which one is ACTIVE which is identified by an ip address indicated by “inet”. Neglect the “loopback port” in the ifconfig displays throughout the experiment. If eth0 shows an ip address, this interface is connected to the production cable & the correct hardware. Now look

at the back of the computer, the Ethernet port where the production cable is connected is blinking (ACTIVE) & that is the eth0 port, shown as “Production = eth0” in Figure 2. So make a note of it.

If eth1 shows an ip address, this is where you want to connect the Green cable. Now look at the back of the computer, the Ethernet port where the production cable is connected is blinking (ACTIVE) & that is the eth1 port which should be used for the Green Cable, shown as “Green = eth1” in Figure 2. So remove the production cable from this port & connect the Green cable to it. Make a note of it

If eth2 shows an ip address, this is where you want to connect the Grey Cable. Now look at the back of the computer, the Ethernet port where the production cable is connected is blinking (ACTIVE) & that is the eth2 port which should be used for the Grey Cable, shown as “Grey = eth2” in Figure 2. So remove the production cable from this port & connect the Grey cable to it. Make a note of it

Repeat using the ifconfig command & check for the eth port which has an ip address (ACTIVE) & follow the procedure above for the remaining cables to connect to the correct hardware Ethernet jack. Later in the experiment when you power on the other devices & connect to other computers, you will see that eth0, eth1, & eth2 become

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active & each with an ip address. Column 3 in Figure 2 shows the correct association (connection) between the colored cables & eth0, eth1 & eth2.

5 Fill in the Hardware (Motherboard, NIC 1, or NIC 2) you identified for each of your computer eth (0, 1, 2) in Column 2 in the table above.

6. Using the ifconfig command, respond to the questions below:

Question (Disregard the loopback port) AnswerWhat is the active eth interface of the computer at your station now?What is the Hardware address (MAC address) of the active interface?What is the IPv4 (inet) address of the active interface (eth0)?What is the broadcast address of the active interface?What is the corresponding netmask (Subnet Mask)?What is the IPv6 (inet6) address of the active interface?What is MTU (Max Transmission Unit) of the active interface?What kind of LAN cable will you use to connect a PC to a switch or a hub?What is the address for the loopback?

7. Send exactly 5 pings to your computer eth0 & check the connectivity. Refer to “man ping” for the command format, & respond to the questions below:

Question Answer with unitsWhat is the ping command you used?Is there proper connectivity to this port? If not, fix it.How many ping packets do you observe?What is the time interval between ping Request packets?What is the minimum round-trip time (RTT) to receive a reply?What is the average RTT to receive a reply?What is the maximum RTT to receive a reply?What is the mean deviation of RTT?Number of packets TransmittedNumber of packets Received% packet lossTime taken for transmissionExplain your observations & comments.

8. To be able to logically connect to other computers in your station over the eth2 interfaces, you need to attach an ip address to each eth2 interface of “to be” the communicating computers. There are two ways to configure this: Using the “ifconfig” command to attach to eth2 of your computer the IP address 192.168.0.x, where “x” is the

host ID. For that you need to enter “sudo ifconfig eth2 192.168.0.x broadcast 192.168.0.255 netmask 255.255.255.0”. “Sudo” takes you to the root level or “admin” level for the port configuration. This is the preferred way at this time.

“x”, the Host-ID of your computer, is equal to za, zb, zc, & zd in the decimal for the Work Area z (1, 2, 3, 4, 5, or 6). For example, for Work Area 1, “x” is

1a=1*16 + 10 = 261b=1*16 + 11 = 27

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1c=1*16 + 12 = 281d=1*16 + 13 = 29

Type ifconfig to check that the eht2 addresses are the same you configured.

Another way to configure the eth2 port ip address is to use the Ubuntu GUI display. You can go to the top right corner of the Ubuntu screen (Figure 3) & click on the vertical up & down arrows (icon). In the dropdown, select & click on “Edit Connection”. You will see three wired eth connections in the computer. You need to click on each connection to find the eth2 wired connection. Select this connection & click on the “Edit” icon on the right to see a display for this connection. Click “IPv4 Setting”. In front of “Method” you will most probably see “Automatic (DHCP) which means that the computer is receiving its ip address via the Dynamic Host Configuration Protocol. In order to manually configure, go to the dropdown on the right & select “Manual”. . Next click on “IP address Setting”. You see a list of the wired connection. Under “Addresses” you need to click on “Add” & enter the following for each of the configuration parameters: 192.168.0.x for Address, 255.255.255.0 for Netmask, 192.168.0.255 for Gateway. Save & OK to get out of the “Edit Wired connection procedure. It should be mentioned that this GUI procedure does not work all the time, so do use it!

Figure 3. Picture of the screen on the Ubuntu PC showing where to edit connection.

9. Check the configuration of the interfaces using the “ifconfig” command & respond to the questions below:

Question Active /Inactive

Hardware address IP address

The status of eth0, its hardware, & ip address?The status of eth1, its hardware, & ip address?The status of eth2, its hardware, & ip address?

You need to do this quickly since eth2 port address may be dropped automatically by the Ubuntu software. Otherwise you need to repeat the ifconfig command above to associate the ip address to it. Any eth interface you need to communicate over must be up.

10. With the eth2 of your computer Active/UP, send 5 pings to it. You can use the “sudo ifconfig eth2 up” command to make sure that eth2 is up. “sudo ifconfig eth2 down” can bring it down. Respond to the questions in the table below.

Question Answer with unitsWhat is the ping command you used?Is there proper connectivity to this port? If not, fix it.What is the minimum round-trip time (RTT) to receive a reply?

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What is the average RTT to receive a reply?What is the maximum RTT to receive a reply?What is the mean deviation of RTT?Number of packets TransmittedNumber of packets Received% packet lossTime taken for transmissionExplain your observations & comments.

CONNECTING TWO COMPUTERS BY HUB

11. Now power on the Asante 2072 Hub & let it warm up. Use a straight-through Ethernet cable to connect the eth2 port of your computer to the eth2 port of computer of one of your partners through the hub at the Patch-Panel. Make sure the related lights on the hub are green so that the two computers are physically connected. Check also the logical connectivity between the computers by the pinging (5 pings) between the eth2 ports of the two computers in your Work Area & respond to the questions in the table below.

Question Answer with unitsWhich computer (A, B, C, D) did you ping?Is there proper connectivity between the two computers? If not, fix it.What is the minimum round-trip time (RTT) to receive a reply?What is the average RTT to receive a reply?What is the maximum RTT to receive a reply?What is the mean deviation of RTT?Number of packets TransmittedNumber of packets Received% packet lossTime taken for transmissionHow long is the RTT of the first packet?How does the RTT of the first packet compare with the other packets?Explain your observations & comments.

12. Repeat the above step using a cross-over Ethernet cable &respond to the questions below:

Question AnswerDo you have any logical connectivity?What are the messages on the computer display?Explain your observations & comments.

13. Repeat step 11 above by pinging from the source the destination with 10 packets of 60,000 FF bytes. At the same time ping from the destination to the source with 10 packets of 60,000 bytes. Respond to the questions below:

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Question Answer with unitsWhat is the ping command you used?Is there proper connectivity to this port?What is the minimum round-trip time (RTT) to receive a reply?What is the average RTT to receive a reply?What is the maximum RTT to receive a reply?What is the mean deviation of RTT?Number of packets TransmittedNumber of packets Received% packet lossTime taken for transmissionExplain your observations & comments.

14. Repeat step 11 above using a packet size of 100,000 bytes & respond to the questions below:

Question AnswerDo you have any logical connectivity?What are the messages on the computer displays?Explain the cause for the message & comment.

CONNECTING TWO COMPUTERS BY SWITCHES

15. Repeat Step 11 but instead of the Asante Hub use & power on one of the Alcatel-Lucent switches OS6860 or OS6450. Connect the cables to the switch, & after a minute check that the related lights at the switch ports are on. Respond to the questions below:

Question Answer with unitsWhich computer (A, B, C, D) did you ping?What Ethernet cables did you use?Is there proper connectivity between the two computers? If not, fix it.What is the minimum round-trip time (RTT) to receive a reply?What is the average RTT to receive a reply?What is the maximum RTT to receive a reply?What is the mean deviation of RTT?Number of packets TransmittedNumber of packets Received% packet lossTime taken for transmissionHow long is the RTT of the first packet?How does the RTT of the first packet compare with the other packets?What is the major difference between the RTTs for hub & the switch?

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16. Repeat step 13 with 10 packets of 60,000 FF bytes in both directions when the two computers are connected by the Alcatel switch OS6860 or OS6450. Respond to the questions below:

Question Answer with unitsWhat is the ping command you used?Is there proper connectivity to this port?What is the minimum round-trip time (RTT) to receive a reply?What is the average RTT to receive a reply?What is the maximum RTT to receive a reply?What is the mean deviation of RTT?Number of packets TransmittedNumber of packets Received% packet lossTime taken for transmissionExplain your observations & comments.Are there any advantages of using a switch over a hub?

CONNECTING TWO COMPUTERS DIRECTLY BY CABLES

17. Now connect the two computers directly via the panel by a straight-through Ethernet cable & repeat step 11. Respond to the questions below:

Question AnswerWhat are the messages on the computer displays?Are the computers connected logically?Explain why the straight-through cable connects or does not connect properly.

18. Connect the two computers directly via the panel by a cross-over cable & repeat step 11. Respond to the questions below:

Question AnswerWhat are the messages on the computer displays?Are the computers connected logically?Why does the cross-connect cable connect or connect properly.What are the differences between the straight-through & cross-over Ethernet cables?What are the advantages of using a switch over a cable?Are the NIC cards you used half-duplex or full-duplex?Which protocol carries the ping packet?

19. Find out about the Asante Hub & Alcatel-Lucent switch & fill in the table? You may need to use the Internet.

Asante Hub Alcatel-SwitchProduct name, model,

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& manufacturers# of Ethernet portsEthernet port speedConfigurability

D. Report 1. Type in your name, group, station, & the computer at the top of the report & all your responses to the questions in the

tables above including your observations & comments neatly. 2. Submit your report by the due date.3. Make sure to bring down eth2 ports, then power off all the devices, remove the cables & return them to the cabinet, &

clean up your station.

*- Figure 1, 2, &3 are from “Sonoma_Lab1_basics_V2, by Dr. Farahmand” with many changes.

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