Third lab

Though you've asked me to move the third lab to next week, you can have a look at it now.

Remember that next Tuesday, November 2nd, we will have the lecture of that week instead of on Friday by popular request.

Units

It was mentioned in the classroom, but given the trouble I can see it has caused you, I would insist on the units we will use. You can have a look at the wikipedia kilobyte entry.

Unless we explicitly use the terms kiB, MiB or GiB or kibit, Mibit or Gibit we always imply units to be powers of 10. So:

1 kByte = 1000 bytes  ( = 8000 bits )
1 MByte = 1000.000 bytes
1 GByte = 10^9 bytes

and

1 kbit = 1000 bits
1 Mbit = 10^6 bits
1 Gbit = 10^9 bits.

Same applies when we mention data rates (bps or Bytes/sec) and file sizes (kB, MB, GB).

Please note that all this is the industry standard too.

Only storage space used to used powers of two as units.

A security vulnerability

Remember the mandatory Host: header of HTTP/1.1. This is where this vulnerability is on a certain web application framework.

Hands-on projects at ETSINF

Last year's ARA students (a group of them) asked for a space for developing group projects somehow related with the studies but not within a given subject entirely. We welcome student initiative and space for a such activities was made available by ETSINF.

This year the same resources (and a better equipped workshop) is available again for personal and/or group projects. This is the public call that was made. That includes a link to the request form in case your team wants to use that resources. If you need some help or advice do not hesitate asking me.

Just in case you wonder, these projects are not pre-defined nor will award you any credits to your studies though you may learn stuff and maybe make new friends (or totally ruin your already scarce social life, who knows).

And we are back ...

Second lab is about several other protocols we will see less of them in the classroom.

Homework

Next lecture readings are Kurose's 2.4 section and [browse] RFC 2045

Individual homework due next class October 26th.

1. Determine the number of bits a geosynchronous satellite link may contain if we know the data-rate is 1Mbps and ground station is located in the equator line. (Remember)
2. Same as before but if ground station is located in Valencia.
3. Two hosts are communicated through a path containing three intermediate routers. If all links' rate is 1Mbps. How long does it take for a 78 KByte file transmitted from one host to be fully received at the other end if packet size is 512 bits.
4. Using the link of problem one, how long does it take for the ground station to upload a 78 KByte file to the satellite (maybe a software update) if packet size is 512 bits and a 20 bits acknowledgment packet has to be send back (and received) before a new data packet can be transmitted? 

First lab

Remember this week we start with the Laboratory sessions 90 min each (10 each semester). For the first one you may want to get familiar with some of the options of wireshark software.

Next week news

Next week Laboratory sessions will start. You can download the lab script.

Please remember that next Monday October 15th, @9:00am there will be the lecture corresponding to October 19th (when I am out of town). The lecture will be held in the usual place: classroom 1E.1.0.

By the way, some very interesting material can be found in this link containing different applets that may help you clarify some of the concepts we are presenting by means of different simulations.

A faster WiFi to replace the current fastest one.

Till now, Wifi (IEEE 802.11) was using two frequency bands: 2.4GHz and 5GHz.  Now a new band is planned. It promises to speed up wireless communications even more than IEEE 802.11ac (latest standard).

Chapter 2 slides

I thought you may want to have them, so here they are. I might use some of the drawings so they can be helpful as far as you do not think slides are a good study tool, because they are not.

Given the activity level on the doodle thing, I guess you are like me: just looking the topic to see what we are up tomorrow. However, if that is the case, I hope you've used some of your time with the homework too.

Moving October 19th lecture

As I mentioned in the classroom I have scheduled a trip to Germany for a technical meeting and I cannot give the lecture of October 19th. This lecture has to be moved and I expect you to decide which day is preferred. Albert suggested to start lectures on Friday (as usual) at 8:00 for two days. I felt it might be a bit tough, but giving it a second thought it is only for two days. Think about it. If you like this approach, please leave a comment on the blog saying so.

On the other hand, we can have the class moved to another day and a Monday seems the ideal candidate. I have created a poll so you can express your preference for this solution. If you prefer this, please provide your answer to the poll.

Another reading

Last lecture, Jorge asked me about Network Security. I mentioned him an article I wrote a while ago about a security incident at UPV. It is not a primer on network security but it shows some common problems. You can get the PDF in Spanish or the English version.

There is an interesting multimedia initiative about Network Security you can find interesting.

I was interviewed by the American magazine Circuit Cellar.

These readings are not mandatory at all.