Due (Problem Set): Wednesday, November 9, 2016,
Due (Programming Assignment): Tuesday, November 22, 2016,
Analyze this trace and answer the questions.
Make sure that you point to a specific piece of information in the
trace that you used to answer the questions.
Describe the application-layer activity captured in the
What version of HTTP is being proposed for the session by the
Does the server agree with the version? How?
What is the client requesting?
How long does it take for the server to respond?
Describe the client application.
What is the purpose of the DNT: 1 directive?
Is the client requesting a persistent connection? How?
Is the server granting a persistent connection?
Describe the server software. What is the common name of this
Does the server permit caching of the document?
What is the MIME type of the returned document. Does it match the
Is the returned document in proper HTML format?
What are the first few characters of the returned document?
Does the server have the correct wall time? Assume the trace
timestamps are correct.
Consider the same trace as in the previous question and focus on the
TCP layer. Draw a sequence diagram of the connection and label it with
the following information:
Show the absolute starting sequence numbers in each direction. It
is fine to give a hex value.
For every packet give its main purpose (e.g., SYN-ACK, DATA, ACK,
etc.) and sequence and acknowledgment numbers (it is OK to give
values relative to the start of the connection).
For every ACK packet indicate which packet it acknowledges.
On both client and server sides, indicate the TCP states (label
the time axis with the state names).
Identify three pairs of packets that could be best used to
estimate the round-trip time (RTT) from client to server and back.
List the observed RTTs and discuss the finding. In your opinion,
what was the round trip latency of the network. Explain your
What are the first few bytes of the public key in the certificate
used by https://colby.edu/? Who issued
In this question you are asked to implement a web-based prefix
calculator similar in functionality to the one that you implemented for
Project 2. Since this is not an exercise in web page development, the
HTML for the solution is provided and should not be modified. A
static (the AJAX request in the page results in a fixed
response regardless of its parameters) example of the page can be found
here. The page served in the trace can be
downloaded from p4/formnjs.html. Using
curl or wget is the easiest way to get the file
to your account on dori. Node.js has been installed on dori. If you have
node.js installed on your machine, you can work on your machine.
Write a node.js server that: serves the provide page
formnjs.html, responds to the AJAX GET
/prefcalc request from the page by returning JSON-encoded
results of the prefix calculation, and returns HTTP 404 Page Not
Found status code for any other request. As with any servers, it
is very likely that your implementation contains significant security
holes that can be easily exploited. For that reason, do not leave your
code running longer than it is necessary for testing. This is also the
reason why the example page uses no active components on the server
Modify the HTML file so that the functionality is provided by a
client-side script embedded in the page. For that you need to remove
the code that you wrote for Assignment 2.
Make your page be able to handle the error messages (e.g. values out
Any interesting extensions you have not tried before.