Experiment No. 2MAC Address and Address Resolution Protocol

• Objective(s):The activity aims to have the students be able to identify the MAC address and discuss the operation of Address Resolution Protocol (ARP).

• Intended Learning Outcomes (ILOs):The students shall be able to:

• show the computer’s MAC address• explain the structure, composition and characteristics of MAC address• demonstrate the operation of Address Resolution Protocol in computer network• show and explain the contents of the Switching Table

• Discussion:

MAC Address

MAC address is the network address used in data-link layer (layer 2) and is assigned to every network adapter of all (layer 2) active devices in the network. It is also known as link address, hardware or physical address. MAC address is used in data/computer network for node to node communication.It is composed of 48 bits and usually expressed in 12 hexadecimal digits. The 48-bit address has two parts, the first 24 bits/6 hexadecimal digits (left side) represents the Organizational Unique Identifier (OUI) which is the same for adapters of the same manufacturer, the second 24 bits/6 hexadecimal digits (right side) is the manufacturer’s assigned and represents the serial number. Each MAC address is unique, that is, there is no instance that two devices have the same.MAC address is written in any of following formats:

A1:34:98:DF:5C:B7A134.98DF.5CB7A1-34-98-DF-5C:-B7A1.34.98.DF.5C.B7

Address Resolution Protocol

The ARP protocol is one of the auxiliary protocols defined in the network layer. It belongs to the network layer and it maps an IP address to a MAC address. ARP accepts an IP address from the IP protocol, maps the address to the corresponding MAC address, and passes it to the data-link layer.Anytime a host or a router needs to find the link-layer address of another host or router in its network, it sends an ARP request packet. The packet includes the link-layer and IP addresses of the sender and the IP address of the receiver. Because the sender does not know the link-layer address of the receiver, the query is broadcast over the link using the link-layer broadcast address. Every host or router on the network receives and processes the ARP request packet, but only the intended recipient recognizes its IP address and sends back an ARP response packet. The response packet contains the recipient's IP and link-layer addresses. The packet is unicast directly to the node that sent the request packet.The arp command is used as a tool for confirming that a computer is successfully resolving network IP addresses to MAC addresses. The TCP/IP network protocol relies on IP addresses like 192.168.14.211 to identify individual devices and to assist in navigating data packets between networks. While the IP address is essential to move data from one LAN to another, it cannot deliver the data in the destination LAN by itself. It uses the MAC address to identify local devices and deliver all data.ARP maintains a table in the computer of IP and MAC address combinations. In other words, it keeps

track of which MAC address is associated with an IP address. If ARP does not know the MAC address of a local device, it issues a broadcast using the IP address. This broadcast searches for the MAC address that corresponds to the IP address. If the IP address is active on the LAN, it will send a reply from which ARP will extract the MAC address. ARP will then add the address combination to the local ARP table of the requesting computer.

• Resources:

• Windows OS Personal Computer (PC) preferably a Laptop w/ Network Interface Card (NIC)• Link-Layer Switch• Straight through Cable (at least one per group)

• Procedure: After every numbered procedure, Go to the numbered Data and Results

• Connect the PC to LAN switch with the Straight Through cable. • The Instructor will assign the management IP address of the LAN Switch• Set the following IP address accordingly in the PC

• Group 1/PC1: IP Address – 192.168.0.2, Subnet Mask – 255.255.255.0• Group 2/PC2: IP Address – 192.168.0.3, Subnet Mask – 255.255.255.0• Group 3/PC3: IP Address – 192.168.0.4, Subnet Mask – 255.255.255.0• Group 4/PC4: IP Address – 192.168.0.5, Subnet Mask – 255.255.255.0• Group 5/PC5: IP Address – 192.168.0.6, Subnet Mask – 255.255.255.0• Group 6/PC6: IP Address – 192.168.0.7, Subnet Mask – 255.255.255.0

• Open command prompt c:\> and type ipconfig <enter>. Record the result particularly the displayed information for the NIC in use (you may take a snapshot image).

• Type ipconfig/all <enter>. Record the result particularly the displayed information for the NIC in use (you may take a snapshot image).

• Type arp –a IP address <enter>. Do this for each of PCs’ IP address including your own.

Ex.: To view the ARP record for PC2: c:\>arp –a 192.168.1.2 <enter>

Record the resulting displayed information (you may take a snapshot image).

• Type ping IP address <enter>. Do this for each of PCs’ IP address including your own.Ex.: To ping PC2: c:\>ping 192.168.1.2 <enter> A reply should be received.

• Repeat procedure no. 6.• View the MAC address table of the LAN Switch (the Instructor will guide on how to view the

MAC address table of the Switch). Record the pertinent information (you may take a snapshot image).

Course: Experiment No.:Name: Section:

Date Performed:• Data and Results:

• Show the information recorded in procedure no.4. • Describe the gathered information/data.

This command displays all current TCP/IP network configuration values and can modify Dynamic Host Configuration Protocol DHCP and Domain Name System DNS settings. The displayed screenshot above shows the Link-Local IPv6 and IPv4 address. The link- local iPv6 address refer only to a particular physical link and are used for addressing on a single link for purposes such as automatic address configuration and neighbor discovery protocol. The IPv4 Address shown is the assigned IP address for our group that we set up prior to the command.

• Show the information recorded in procedure no.5. • Describe the gathered information/data and the difference compared to procedure no. 4.

For Ipconfig/all displays all of the current TCP/IP configuration values, including the IP address, subnet mask, default gateway, and Windows Internet Naming Service (WINS) and DNS configuration. The DHCPv6 or Dynamic host configuration protocol version 6 IAID is the identifier for an IA (identifier association) chosen by the client. Each IA has an IAID, which is chosen to be unique among all IAID’s. The DHCPv6 Client DUID is also displayed. The DHCP Unique Identifier (DUID) is used by a client to get an IP address from a DHCPv6 server. The Link-local IPv6 address and IPv4 address are also displayed together with subnet mask.

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• Show the information recorded in procedure no.6. • Describe the gathered information/data.

The screenshot shows the use of ARP or address resolution Protocol. The Address Resolution Protocol (ARP) allows the computer that we used to find the MAC address of the other computers with an IP address on the same physical network or switch. These entries are added and deleted automatically during normal use of TCP/IP sessions with remote computers. Dynamic entries age and expire from the cache if not reused within 2 minutes. If a dynamic entry is reused within 2 minutes, it may remain in the cache and age up to a maximum cache life of 10 minutes before being removed or requiring cache renewal by using the ARP broadcast process.

• Show the information recorded in procedure no.8. • Describe the gathered information/data and the difference compared to procedure no. 6.

The ping command helps to verify IP-level connectivity. When troubleshooting, you can use ping to send an ICMP echo request to a target host name or IP address. We are able to make a connection with the other computers or nodes connected to the switch. It shows the IP address of the other nodes. Use ping

whenever you need to verify that a host computer can connect to the TCP/IP network and network resources. You can also use ping to isolate network hardware problems and incompatible configurations.we are able to make a connection with the other computers or nodes connected to the switch. It shows the IP address of the other nodes.

The following are described in this command:• The first line tells us what the command is doing. It will repeat the address you put in and tell you

how much data is being sent.• A successful Ping command will return lines that display how long it took the address to respond.

TTL represents the number of hops that occurred during the packet transfer process. The lower the number, the more routers the packet passed through. Time is how long in milliseconds the connection took.

• After the operation is completed a summary of the results will be displayed. Lost packets mean your connection to the address is unreliable, and data is being lost in the transfer. The summary will also display the average time the connection took.

• Show the information recorded in procedure no.9. Describe the gathered information/data.

The MAC address table shows the Mac address of the computers or nodes connected in the switch. Also the port numbers where our wire is connected are shown in the MAC address table.

• Observation

• the ipconfig command is used to find out current TCP/IP settings. With IPCONFIG we can find out our IP Address, find our Default Gateway and find our Subnet Mask. This is a very handy network tool for finding our local IP address.

• the ipconfig/all command display all our IP information for all adapters. With ipconfig /all we can also find out our DNS Server and MAC Address. This shows our full TCP/IP configuration for all adapters on our Windows machine. We can find out your own IP Address as well as your default gateway.

• the arp-a command enables us to find out the MAC address of the device you are connecting to. It comes with two entries, the dynamic and static. in our case, we had a dynamic entry.

• The ping command helps to verify IP-level connectivity. When troubleshooting, we can use ping to send an ICMP echo request to a target host name or IP address. Use ping whenever we need to verify that a host computer can connect to the TCP/IP network and network resources. You can also use ping to isolate network hardware problems and incompatible configurations.

• Conclusion

the activity lets us to determine the MAC adresses and show the operation of Address Resolution Protocol. In performing this experiment, I have conlude that TCP/IP allows an application to communicate over a network with another computer by using either an IP address using the command prompt. Through the use of a switch, we were able to establish connection. However, regardless of which naming convention is used, the destination must ultimately be resolved to a hardware address (media access control (MAC) address) for shared access media such as Ethernet. MAC address is the network address used in data-link layer (layer 2) and is assigned to every network adapter of all (layer 2) active devices in the network. It is also known as link address, hardware or physical address. MAC address is used in data/computer network for node to node communication.

• Recommendation

In taking this experiment, I recommend that each active devices that are connceted to the switch must first check the type of wire they are going to use in the set up. UTP cables may have different data rate capacity. The higher, the better. Next, check the switch if you are connected to it. You can see an LED light that appers whenever the switch detects the computer at the other end of the line. When the LED turn on, that means, you are already connected. While undergoing the procedure, it is important that each of us must take it politely all together at the same time. Early configuration to other groups may lead to undesired information.

• Assessment

CRITERIA BEGINNER1

ACCEPTABLE2

PROFICIENT3 SCORE

I. Laboratory Skills

Manipulative Skills

Members do not demonstrate needed skills.

Members occasionally demonstrate needed skills

Members always demonstrate needed skills.

Experimental Set-up

Members are unable to set-up the materials.

Members are able to set-up the materials with supervision.

Members are able to set-up the material with minimum supervision.

Process SkillsMembers do not demonstrate targeted process skills.

Members occasionally demonstrate targeted process skills.

Members always demonstrate targeted process skills.

Safety Precautions

Members do not follow safety precautions.

Members follow safety precautions most of the time.

Members follow safety precautions at all times.

II. Work Habits Time Management / Conduct of Experiment

Members do not finish on time with incomplete data.

Members finish on time with incomplete data.

Members finish ahead of time with complete data and time to revise data.

Cooperative and Teamwork

Members do not know their tasks and have no defined responsibilities. Group conflicts have to be settled by the teacher.

Members have defined responsibilities most of the time. Group conflicts are cooperatively managed most of the time.

Members are on tasks and have defined responsibilities at all times. Group conflicts are cooperatively managed at all times.

Neatness and Orderliness

Messy workplace during and after the experiment.

Clean and orderly workplace with occasional mess during and after the experiment.

Clean and orderly workplace at all times during and after the experiment.

Ability to do independent work

Members require supervision by the teacher.

Members require occasional supervision by the teacher.

Members do not need to be supervised by the teacher.

Other Comments/Observations: Total Score

• Reference(s):B.A. Forouzan, Data Communications and Networking, 5th Edition, McGraw Hill, 2013http://highered.mcgraw-hill.com/sites/0073376221/student_view0/lab_assignments.html