Unit 5. LAB 5 Ethernet LANs
LAB 5.1: LAN Standard
Exercise 5.1.1
Briefly define the 802.1 standard: Keeper of the LAN architecture – IEEE standard 802. Describes the 802 family of standards. Describes the LAN Architecture. Defines some useful things, such as the LAN address format, the SNAP protocol, the Playpen Ethertypes, and the OID registration arcs. The higher Layer Interface working group in 802. Defines the bridging and security glue that interconnects the LANs define by the 802 MAC groups.
Exercise 5.1.2
What 802.3 standard originally define PoE functionality? When was the standard enhanced, and what was the new standard name given for the enhancement? The standard that originally defines PoE functionality was the IEEE 802.3af. The new standard is known as IEEE 802.3at it, and it was enhanced in 2012.

Exercise 5.1.3 Complete Table Standard | Cabling | Maximum Length | 10BASE5 | Coaxial(Thicknet) | 500m | 10BASE2 | Coaxial (Thinnet) | 185m | 10BASE-T | UTP (Cat3, 5, 5e, 6) | 100m | 100BASE-FX | Multi-mode fiber optic cable (SC or ST) | 400m | 100BASE-T | UTP (Cat3, 5, 5e, 6) | 100m | 100BASE-T4 | STP Twisted Cable | 100m | 100BASE-TX | Single-mode fiber optic cable | 20km | 1000BASE-LX | SMF and MMF | 550m | 1000BASE-SX | MM fiber-optic | 220m or 550m (dependent upon fiber thickness | 1000BASE-ZX | MM fiber-optic | 550m | 1000BASE-T | UTP (Cat3, 5, 5e, 6) | 100m |

Exercise 5.1.4
What does the numeric prefix before BASE in the Ethernet standards define? What does the inclusion of a postfix of – T imply? The numeric prefix means the number of Mbps transmission speeds the Ethernet standard supports. T implies twisted pair.

LAB 5.2: MAC and IP Addresses
Exercise 5.2.1
Why must a MAC address have unique for every NIC produced? What effect will it have on the network if two devices from two different manufactures share the last 24-bits of their MAC addresses? Like your mailing address at home, your computer's NIC has a unique address. This address must be unique in the entire world. Otherwise, network traffic couldn't find its way to the right computer.
Exercise 5.2.2
What information about the network connection is given on the Support tab of the status window?
The IP address information, subnet mask, and default gateway.
Exercise 5.2.3
What is the physical address (MAC address) of the NIC (or network adapter) for this connection?
Physical Address: 20-7C-8F-1F-DC-68
Exercise 5.2.4
Who is the manufacturer for your NIC? What information is given about the manufacturer?
Here are the results of your search through the public section of the IEEE Standards OUI database report for 20-7C-8F:

20-7C-8F (hex) Quanta Microsystems,Inc. 207C8F (base 16) Quanta Microsystems,Inc. No.5 Lane 91,Dongmei Rd. Hsinchu 300 TAIWAN, PROVINCE OF CHINA Exercise 5.2.5 What is the IP address of your NIC or network adapter? What is the IP address listed for your default gateway? IP address: 192.168.0.15; Default Gateway: 192.168.0.1 Exercise 5.2.6 What steps are involved and how is each message sent (broadcast to all devices or unicast to single device? Step 1: When a source device wants to communicate with another device, source device checks its Address Resolution Protocol (ARP) cache to find it already has a resolved MAC address of the destination device. If it is there, it will use that address for communication. To view your Local Address Resolution Protocol (ARP) cache, Open Command Prompt and type command "arp -a" (Without double quotes using Windows Operating Systems).
Step 2: If ARP resolution is not there in local cache, the source machine will generate an Address Resolution Protocol (ARP) request message, it puts its own data link layer address as the Sender Hardware Address and its own IP address as the Sender Protocol Address. It fills the destination IP address as the Target Protocol Address. The Target Hardware Address will be left blank, since the machine is trying to find that.
Step 3: The source broadcast the Address Resolution Protocol (ARP) request message to the local network.
Step 4: The message is received by each device on the LAN since it is a broadcast. Each device compare the Target Protocol Address (IP Address of the machine to which the source is trying to communicate) with its own Protocol Address (IP Address). Those who do not match will drop the packet without any action.
Step 5: When the targeted device checks the Target Protocol Address, it will find a match and will generate an Address Resolution Protocol (ARP) reply message. It takes the Sender Hardware Address and the Sender Protocol Address fields from the Address Resolution Protocol (ARP) request message and uses these values for the Targeted Hardware Address and Targeted Protocol Address of the reply message.
Step 6: The destination device will update its Address Resolution Protocol (ARP) cache, since it need to contact the sender machine soon.
Step 7: Destination device send the Address Resolution Protocol (ARP) reply message and it will not be a broadcast, but a unicast.
Step 8: The source machine will process the Address Resolution Protocol (ARP) reply from destination, it store the Sender Hardware Address as the layer 2 address of the destination.
Step 9: The source machine will update its Address Resolution Protocol (ARP) cache with the Sender Hardware Address and Sender Protocol Address it received from the Address Resolution Protocol (ARP) reply message.
Exercise 5.2.7
Exercise 5.2.8
Run the command arp –a again to see the effect it has on the table. What is the IP address that is added? What is the MAC address that was added? Use the –s argument to add a new address to the table to match IP address 101.0.0.1 to the MAC Address 00-AA-00-11-11-11. What command did you use to add the address pair? What is displayed as the type for these pairs?
IP address: 192.168.0.15; MAC Address: 7c-b2-1b-2d-8e-32arp. Arp –s is the command use to add the address pair.

Exercise 5.2.9
Use the arp –a command to verify that the entry is removed. What command will you use to remove the pairing to MAC address 00-AA-00-11-11-11 that you entered as astatic pair in the table?
-d: deletes the host specific by inter_addr.
LAB 5.3: Finding Network Settings
Exercise 5.3.1
What information is displayed as a result?

Are the entries the same for the IP address and for the default gateway? Yes they are the same.
Exercise 5.3.2
What address is returned as the IP address of localhost? How many times is the ping message sent by default? IP address: 192.168.0.15. The ping message was send 4 times.
Exercise 5.3.3
Ping 192.168.1.1. How much time (in time=part of the output) did it take for the ping to response to come back to the local machine? If there were different values, report the average response time.
At first the request was timed out three times. Packets send 4, packets received 0, lost packets 4. It took 2ms, average time 1ms.
Execute the following command from the command –line interface:
Ping www.google.com
How much time (on average) did it take to get a response from the host? How does this compare to the time it took to get a response from the default gateway? Choose another web address and send a ping command to it. Did the ping command get a response? If so, how long did it take (on average)? What makes a difference in the timing of these messages?
It took www.google.com on average of 212ms to get a response. It took the default gateway an average of 1ms.
It took www.yahoo.com on average of 284ms. The reason why some web address takes longer to send a response is how devices they have to go through to get to their destination. Yahoo may be further than Google.
Exercise 5.3.4
Ping –a 192.168.1.1. What is the name of the host for the default gateway? Use this argument to ping localhost. What name does it return? I didn’t get any name for the default gateway. The name return was the localhost computer’s name.
Exercise 5.3.5
Ping –n 6 192.168.1.1. What is the benefit of being able to send a set of number of ping messages to a host? Pings the local host, this will allow you to see if the computer is able to send information out and receive the information back. Note that this does not send information over a network but may allow you to see if the card is being seen.
Exercise 5.3.6
Tracert 192.168.1.1. How many devices are returned in the path between your machine and the default gateway? 14 devices
Now you will use the tracert command to access to different web host and compare devices returned in the path. Tracert www.google.com
Host www.google.com went through 18 devices to get to the local host, while host www.yahoo.com went through 14 devices to get to the local host. Which the distance between the local host and google is furhter than the distance between yahoo and the local host.
Exercise 5.3.7
Run nestat command (without any arguments) on your machine from the command-line interface. How many active connections are returned? What protocols are in use? TCP protocol.
Open a web browser such as Internet Explorer and enter a destination web address in the address bar. When this page has loaded, run netstat command from the commna-line interface again. How many connections are returned this time? Where did these connections originate?
Netstat will provide all established connections for both network and domain sockets. That means we’ll see not only the connections that are actually working over the network, but also the interprocess communications (which, from a security monitoring standpoint, are not useful). So in the command just illustrated, we have asked netstat to show us all ports (-a)—whether they are listening or actually connected—for TCP (-t) and UDP (-u).
LAB 5.4: Basic Network Troubleshooting
Exercise 5.4.1
What command would you use to get this information? Give the command sequence you would enter at the command line to retrieve this information. The ping command to get this information. Ping –a and Ping –n.
Exercise 5.4.2
What is the best command to determine whether all the hosts on the local-area network are reachable?
Ping host and then ipconfig/all
Exercise 5.4.3
If your computer is unable to reach the internet, what is the best way to determine where the error is occurring using command-line networking? Give the command sequence you would use to determine this. Ping command and tracert command.
Exercise 5.4.4
If your local machine is not connecting to any other host on the network, what two command will give you information on whether your network device is active and the current configuration of your NIC or adapter? Net Stat is a tool that tells you what your machine is connected to at the moment the command is run. This makes it a very useful tool to see if your machine is connecting to servers that you don't know about.