Due: a start of class Oct 12 Networks Midterm 1 Due: a start of class Oct 12 Name ______________________________

Instructions You are asked to gather data using wireshark and answer the following questions. I expect well documented and well written answers including sample output. Actions Start Wireshark and start a capture session Open the web page www.plu.edu End the capture session

Question 1 Examine the trace and find the exchange of packets between your machine and the web server (the host providing the web pages to your machine). Can you find an example packet in this exchange where the packet contains details about the type of your web browser (e.g., if it is Fire Fox, Internet Explorer, etc.) being used? If you can find this then what is the value of this attribute in your particular trace? Why is this information given? ___ of 5

Question 2 In the trace you can see many protocols listed! Some of these protocols are called transport protocols. Which transport protocol is used between your machine and the web server? Why would you think this one is used instead of an alternative? You will see that other protocols are captured in your trace. One such protocol is HTTP. What is the relationship between the transport protocol you identified and HTTP? Both protocols are used to satisfy your browser's request for a web page. Why was more than one protocol used? ___ of 20

Question 3 In the trace you will find IP addresses within the packets. Find an example packet in the trace where the IP address associated with your machine is present. Provide this example packet with your answer. Why is the IP address present in the particular packet you selected (what purpose does it serve)? How are IP addresses and port numbers used, to address what specifically? ___ of 10

Question 4 We discussed protocol layers in class. Which layer is the IP associated with and why isn’t it associated with say the application layer? ___ of 10

Question 5 Each node has a unique Link Layer MAC address. Can you find the MAC address for your machine within this trace. What is the MAC address of your machine? Provide a trace of the packet in which you found it. Why do you think a MAC address is needed given that your machine has an IP address? ___ of 10

Question 6 Consider the short trace you just captured. You will see many different protocols listed in the trace. Excluding the HTTP and TCP protocols identify one of these other protocols. Describe why this protocol is being used and what it is all about (Google it and summarize the service it offers. Recall a protocol is the core of a layer that provides a service to a higher layer – what is this service for one of the protocols in your list other than the obvious ones DNS, TCP, HTTP). ___ of 20

Question 7 You have trained your dog to carry 10 DVDs to a specified destination. Each DVD contains 4 gigabytes of information. Suppose that your dog travels at 10 Km/hr. For what range of distances does your dog have a higher data rate than a 155 Mbps transmission line?   ___ of 10

Question 8 Why is UDP used instead of TCP in applications such as video streaming? ___ of 10

Question 9 Sketch the encoded bit stream for 1101111001 using Manchester encoding. Why is Manchester encoding used? ___ of 10