Back to the game

Please remember next Wednesday 28th at 10:00 the retake exam will be held. As with the previous one, the use of calculators or phones is not allowed.

Our subject's lectures for the second term start this Friday next Wednesday 12:30, so I see you all in the classroom. We will start with the first section of Chapter 4 from the textbook.

Please note exams have been marked and those who attended the retake should have received an email with a link to check the marking of your exam (if you should and you have not received the email, please let me know).

1st term marks are out

You can find them on the link

I know that some of you could not make it for various reasons and I expect you for the retake. In case you are wondering, you can go to the retake exam next week even when you did not do last Monday's exam).

My first impression is that some of you did not study enough for the exam as I reckon this exam was within what was expected and still average performance is poor.

Please note the blue background column represents the mark of the whole term, all things considered (class, homework, labs, exam).

You can review your marking in this link. If you find any error, please let me know so I can fix it. Marked exams will be available only for week.

You do not need to obtain a minimum mark on any term, your first time mark will be averaged with your second term one. However, if you have a very low mark now, it is advisable you try to improve it in the retake exam (if you want to). Students doing the retake exam need to know that the new mark they obtain will be replacing the mark they scored in the first exam. If you score more poorly in the retake exam you can actually worsen your mark.

Solved exam 1st term

You can download 1st term solved exam from here. Solved exam is in Spanish. Please let me know if you have any problem with the answers. I am now busy marking the exams so you can have them ASAP.

A couple of questions that you may have

Some exercises use 2 MSS as the initial valuefor the congestion window, why is that?
It's ok. In the book and in the classroom an initial value of 1 MSS is used instead. Modern TCP implementations are commonly using 2 MSS instead. That is why you can see this value sometimes.


What happens after a loss event in TCP congestion control?
In the book and in the classroom we have mentioned the new threshold value is half of current congestion window[RFC2001]. However, once you factor in that flow-control does limit the sending capability of the sender, what we call the transmission window is the number of segments that can actually be transmitted and it is equal to min(receiverWindow, congestionWindow). Modern TCP implementations use half of the used transmission window as the new value for the threshold after a loss event[RFC2581]. That means that the new threshold could be lower than just half of the congestion window.

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The only purpose of this information is for your own peace of mind, given that some of you have detected some contradiction between the book/lectures and some of the solved exercises out there.

First term exam

Exam will be held in classroom 1G 1.4 next Monday January 19th at 15:00h.

And we are back from winter break

Welcome you all. This week we'll have the last lecture of the term and then we will have the exam's pause next. I want to remind you that some solved exams can be found online.  You can get some more past exams from an older blog but please note that last exam format is no longer what you would expect but it is still useful for checking your own understanding.

Please be reminded that during the exam's pause you are still entitled to stop by my office with any questions you may have about the subject. As usual, send me an email for an appointment.