Computer Networks

Let's keep in touch

While I do know some of you are going to stay around for a while, others are already back to your home country. Because many of you are using the university provided email, contact will be lost as soon as your account has expired.

You still can reach me on Facebook or Linkedin networks, and I think it is a good idea to keep the link on. Sometimes you may need a recommendation letter or discuss any technical issue. Other times I may ask for some traveling advice. Who knows.

So farewell and see you online.

Challenge your programming skills

The new edition of Google's CodeJam contest is about to start. While you won't get any points on this subject, it can be fun and you can also get some cash!

Summer reading

I've found this article on Tom's hardware website quite interesting to read.

Spicing up your marks

After some changes on the marking due to your requests, marks have been adjusted so all the available range of the pass mark is covered. As a result some of the marks actually crossed the fail/pass border and those of you affected will be pleasantly surprised. Still some of you did not make it and you will have to come back in September for another exam. Please note the exam "algorithm" will be the same as in June: You can take 1st term, 2nd term or both exams.

REDES-2008_09

Publish at Scribd or explore others:

Do you want to check your exam?

Please note you'll need to scroll down to find your exam. They are not stored in any special order, so be patient.

1st term exam

and

2nd term exam

are available for you to see them on-line (no download is allowed).

Exams will only be available for a limited time.

Update: Question 21 of 2nd term exam has been re-examined and now Dijkstra is also considered a valid answer. Marks have been modified accordingly for all of you.

June 2009 2nd and 1st term solved exams

As we did before, please double check the solved exam and with the answers you remember you provided and then, mark your own exam and email the mark to me.

Thanks.

Jun2009A Solved

The 1st term exam solution is below. As with the other exam, please mark yours and email it.

Jun2009B Solved

A few more solved exams

If you took the time to explore this blog's content backwards you've realized some of the older links are dead. But fear not, some of that content is brought back to life here. These are a few solved exams more for you to look at.

Don't forget next Monday we'll have the exam.

Either you are attending to one term exam or two, see you there.

Breaking bad

Some years ago we've got a situation at UPV. This paper details some of the events that happened. I reckon both students involved are still at UPV.
Paper

Publish at Scribd or explore others: Technology Business & Law computer breakin intrusion

Exam details

Next June 2009 exam will consist of two parts. Those of you only interested on the second term part have to come at 10:00. 2nd term exam will last two hours.

After the 2nd term exam a 1st term exam will be held (same place but fewer rooms).

Please note that it is mandatory you take now the 2nd term exam but the 1st term one is optional. If you are happy with the mark you already have got in the 1st term then you do not need to repeat that. Your final mark will average the mark of both semesters "no strings attached".

Both exams will follow a similar format than the ones on the blog (sorry but old links may not work).

Improve your Spanish while learning cryptography

Manuel Lucena is a professor from Jaen University who has a great book on cryptographic algorithms and who is kind enough to provide us a free PDF version.

There is only a catch on this offer: it's only available in Spanish. What a good opportunity for practicing your newly acquired skills!!

Contrary to what happened in the classroom, the book provides a detailed view of many cryptographic algorithms, including DES, IDEA, AES, RSA, ElGamal, DSA, ... etc

Update: For those of you that still prefer a book written in English you can download this one. Though a bit aged it is still a very solid book.

Put your crypto skills to work

For many of you [non-Spaniards] this might be a more difficult challenge as Spanish knowledge can help. Can you discover what is the hidden part of this message?

You are welcome to bring the solution to the class and I'll pay you a coffee.

For more challenging proposals you can go to this contest.

Last two chapters

Chapter 6 and Chapter 8 are the last chapters of our course. There is not much time left and we will skip some of the sections, please stay tuned to get the details about what is left out.

Lab#10

This is the last lab of the course. Click on the title to get the file.

More info here.

Easter Fun

Now that we're approaching the end of the course you might be eager to see the whole thing in action. There is no better way to learn anything that when you're facing the task of building a working system. And I mean to build all of it!

Most of the time you work on a personal computer. Not the hardware or the operating system are part of what you have to build. In an extreme case you might be rebuilding the kernel of the operating system you're running.

If you like hardware and to experiment I propose you to get one Arduino board and a LAN adapter for it. I've used in the past the ones I'm referencing and I've found that seller the cheapest option at the time.

To get things running you'll need to download the software library for the LAN card plus the Arduino IDE appropriated for your computer (OS X, Linux or Windows).

Arduino is an easy-to-use low-cost "open hardware" microcontroller board around ATmega168 chip. USB bus server to both power the board and download developed code to it. Many extensions are possible and the LAN card adds a simple Microchip LAN controller to Arduino. All the source code you see is all what's available: no operating system below, no hidden strings, just the bare source of the library.

Lab#9

Click on the title.

Error checking (kind of)

If you want to know the character (for error control purposes) of a Spanish identification document, just perform the modulo 23 operation over the DNI number. Then use the next table. That's it.

0	T	12	N
1	R	13	J
2	W	14	Z
3	A	15	S
4	G	16	Q
5	M	17	V
6	Y	18	H
7	F	19	L
8	P	20	C
9	D	21	K
10	X	22	E
11	B

And if you want to get a better idea about how CRC works you can visit this old post. There is a detailed Wikipedia article too.