COS332 - Computer Networks
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Typo on memo
Posted By : Prof Martin Olivier on 29 May 2010, 11:07
The correct answer for Q6(3) is G.
Semester marks published
Posted By : Prof Martin Olivier on 20 May 2010, 14:24
The semester marks have been published below. If there are any inaccuracies, remember the famous phrase on the cover of the Hitchhiker's Guide to the Galaxy and act accordingly. We can rectify inaccuracies (if there are any) in V0.1.
Chapter 9 released
Posted By : Prof Martin Olivier on 14 May 2010, 11:21
Chapter 9 of the study material has been released on netw.co.za.
A complete version that does not add any new material, but integrates all earlier material and corrects some typos and similar issues, has also been released. Thanks to all who helped to spot problems. Further help to spot remaining issues will be appreciated.
A complete version that does not add any new material, but integrates all earlier material and corrects some typos and similar issues, has also been released. Thanks to all who helped to spot problems. Further help to spot remaining issues will be appreciated.
CRCs - Corrigenda
Posted By : Prof Martin Olivier on 14 May 2010, 07:39
A couple of you have noticed the silly mistake in Section 8.4.3 (CRCs) of the handbook: 1-0=0...
An updated version of that section is now available on netw.co.za.
An updated version of that section is now available on netw.co.za.
Chapter 8 is available
Posted By : Prof Martin Olivier on 3 May 2010, 21:48
Chapter 8 (on layer 2) is available. Please read it. Ensure that you know exactly how Hamming code works by next Tuesday (11 May).
Mark Queries
Posted By : Mr Francois Mouton on 30 Apr 2010, 11:53
The semester test is available at the cosidesk from today onwards. On Wednesday, 5 May 2010, all mark queries will be dealt with in the ICSA lab between 1pm till 2:30pm. Use this slot for any queries on pracs, class tests and semester test.
Take note that all the small class tests and big class tests will be available for collection in the query session.
Take note that all the small class tests and big class tests will be available for collection in the query session.
Marks
Posted By : Mr Francois Mouton on 23 Apr 2010, 11:53 (last modified on 23 Apr 2010, 12:15)
The marks have now been released. These marks are up to date up to 23 April. If you have any queries on the marks, there will be a 2 hour slot next week in which you can query the marks. The time for this slot will be made public very soon.
Queries will only be dealt with in that session, so please keep all your queries until that time.
Queries will only be dealt with in that session, so please keep all your queries until that time.
Consultation hours
Posted By : Prof Martin Olivier on 20 Apr 2010, 11:42
I will not be available for consultation during my normal consultation hours on Wednesday, 28 March, since that Wednesday is officially a Monday.
I will also not be available for consultation during my normal consultation hours on Wednesday, 5 May, but will be in my office for most of Thursday, 6 May. You are welcome to come and talk to me then.
I will also not be available for consultation during my normal consultation hours on Wednesday, 5 May, but will be in my office for most of Thursday, 6 May. You are welcome to come and talk to me then.
New material posted; semester test scope
Posted By : Prof Martin Olivier on 11 Apr 2010, 23:32
Some new prescribed material (Chapters 4-7) has been posted. Given the little time that remains before the semester test, only that work in the new material that has been discussed in class (plus all the old material and pracs) will be examined in the semester test.
Ignore Chapter 4 for the time being.
We will discuss the overlap between class work and Chapters 5-7 during Tuesday's lecture.
For the sake of clarity: The semester test will cover all work discussed thus far in class, as well as anything you had to do thus far for a prac. In addition, Chapters 1-3 will be covered in the test, including any material it contains not discussed in class. Chapters 5-7 may help you to understand something better that was discussed in class, but no new work in those chapters will be tested.
Ignore Chapter 4 for the time being.
We will discuss the overlap between class work and Chapters 5-7 during Tuesday's lecture.
For the sake of clarity: The semester test will cover all work discussed thus far in class, as well as anything you had to do thus far for a prac. In addition, Chapters 1-3 will be covered in the test, including any material it contains not discussed in class. Chapters 5-7 may help you to understand something better that was discussed in class, but no new work in those chapters will be tested.
New RFC
Posted By : Prof Martin Olivier on 2 Apr 2010, 14:15
An important new RFC has just been published: RFC 5841. Please study it before the next lecture.
Big class test memo
Posted By : Prof Martin Olivier on 31 Mar 2010, 10:02
Here is the memo for yesterday's big class test - somewhat later than I anticipated. It is represented using row-major order.
AEBCA
CAADD
ABCED
AEBCA
CAADD
ABCED
A challenge
Posted By : Prof Martin Olivier on 24 Mar 2010, 11:53 (last modified on 24 Mar 2010, 11:58)
I today received a spam message that the headers claim originated from 121.11.149.250. If the headers are correct, where in the world did the message originate from?
The headers claim that 121.11.149.250 is associated with up.ac.mz. Does this domain exist? To whom is it registered? Does it correspond with 121.11.149.250 in any way?
Why would someone use an address like up.ac.mz to spam me?
Some other interesting remarks: The message was sent by "Global SpringerLink Finance Investments". (Why is this interesting?) The message was sent using a time of GMT+2. (Why is this interesting?)
The path the message seems to have followed is 121.11.149.250 to 127.0.0.1 to 127.0.0.1 to 196.3.96.162 to 137.215.101.101 to 137.215.40.17. Does this make sense?
Can we catch the guilty party?
Let's discuss this in class on Friday.
The headers claim that 121.11.149.250 is associated with up.ac.mz. Does this domain exist? To whom is it registered? Does it correspond with 121.11.149.250 in any way?
Why would someone use an address like up.ac.mz to spam me?
Some other interesting remarks: The message was sent by "Global SpringerLink Finance Investments". (Why is this interesting?) The message was sent using a time of GMT+2. (Why is this interesting?)
The path the message seems to have followed is 121.11.149.250 to 127.0.0.1 to 127.0.0.1 to 196.3.96.162 to 137.215.101.101 to 137.215.40.17. Does this make sense?
Can we catch the guilty party?
Let's discuss this in class on Friday.
Practical 6
Posted By : Mr Francois Mouton on 18 Mar 2010, 14:22
There are quite a few public SMTP servers you can use. If you are still struggling to use the smtp servers which are offered by campus you can try the following ones:
smtp.saix.net
smtp.telkomsa.net
smtp.is.co.za
If these ones still fail, use the one which is provided by your ISP.
If after all these suggestions you still struggle. Register either a yahoo, hotmail or gmail account and use their smtp server. There is really many various options that you can use.
Lastly, do note that you are obviously not allowed to use "import javax.mail" at all as this implements the protocol for you. Any program which uses javax.mail will receive 0.
smtp.saix.net
smtp.telkomsa.net
smtp.is.co.za
If these ones still fail, use the one which is provided by your ISP.
If after all these suggestions you still struggle. Register either a yahoo, hotmail or gmail account and use their smtp server. There is really many various options that you can use.
Lastly, do note that you are obviously not allowed to use "import javax.mail" at all as this implements the protocol for you. Any program which uses javax.mail will receive 0.
Practical 5
Posted By : Mr Francois Mouton on 18 Mar 2010, 14:18
The PGP server for Practical 5 is up an running. Use all the details as specified in the practical but a different public key should be used.
The practical should be completed within 7 days from this announcement. Thus the cut-off date for this practical is now Thursday the 25th.
The public key is as follows:
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1.4.10 (GNU/Linux)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=tPVN
-----END PGP PUBLIC KEY BLOCK-----
The practical should be completed within 7 days from this announcement. Thus the cut-off date for this practical is now Thursday the 25th.
The public key is as follows:
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1.4.10 (GNU/Linux)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=tPVN
-----END PGP PUBLIC KEY BLOCK-----
Semester test
Posted By : Prof Martin Olivier on 16 Mar 2010, 15:56
The semester test is to be written one month from today: Friday, 16 April. Normal lecture period. Normal lecture venue.
Server for Prac 6
Posted By : Prof Martin Olivier on 16 Mar 2010, 15:51
Try using student.up.ac.za for Prac 6 from campus (and your ISP's server from home). Student works from my office, but I don't have the rights to test it from the lab...
Prac 5 on ice
Posted By : Prof Martin Olivier on 16 Mar 2010, 15:50
Prac 5 is on ice until the server works. You will get at least a week's notice before Prac 5 will really be due. In the meantime we continue with Prac 6 as scheduled.
PGP is available at CS
Posted By : Prof Martin Olivier on 10 Mar 2010, 12:08
See
ftp://ftp.cs.up.ac.za/Software/Networks/GNUPG/PGPDesktop9.10.0_Windows.zip
or, for the sake of brevity, http://tinyurl.com/pgpprac
ftp://ftp.cs.up.ac.za/Software/Networks/GNUPG/PGPDesktop9.10.0_Windows.zip
or, for the sake of brevity, http://tinyurl.com/pgpprac
Problem with Prac 5 server
Posted By : Prof Martin Olivier on 10 Mar 2010, 11:31
The Prac 5 server is not running as it should. When it does run you will receive a reply - positive or negative. If you get no response your email
has simply been queued until it runs again. We will extend the due date for this prac by about a week to address the issue. In the meantime, make sure that you can communicate with friends using PGP/GPG.
has simply been queued until it runs again. We will extend the due date for this prac by about a week to address the issue. In the meantime, make sure that you can communicate with friends using PGP/GPG.
Problem with example.za.org
Posted By : Prof Martin Olivier on 10 Mar 2010, 07:33 (last modified on 10 Mar 2010, 08:11)
I recently registered example.za.org, but it's not working. The problem occurs somewhere in the DNS. I think I know where the problem is, but to allow you to test your diagnostic skills I plan to leave it broken for a few days. Is anyone able to pinpoint the wrong entry/entries in the DNS?
BTW I am not referring to example.org.za, which works fine.
BTW I am not referring to example.org.za, which works fine.
News24 story on domain squatting
Posted By : Prof Martin Olivier on 10 Mar 2010, 07:29
Read the following News24 story on domain squatting in za: http://tinyurl.com/zadna
The price of some domain names
Posted By : Prof Martin Olivier on 5 Mar 2010, 14:02
According to dnjournal.com:
"Sedo's roster included four ccTLDs that broke through the strong .com defensive line to take places on the elite [price] list. Two of those country codes landed in the top ten; #4 Furniture.co.za (South African ccTLD) at $33,000 and #8 MO.de (German ccTLD) at $21,039." [Thanks to Philippo for pointing this out]
"Sedo's roster included four ccTLDs that broke through the strong .com defensive line to take places on the elite [price] list. Two of those country codes landed in the top ten; #4 Furniture.co.za (South African ccTLD) at $33,000 and #8 MO.de (German ccTLD) at $21,039." [Thanks to Philippo for pointing this out]
No consultation hours on 17 March
Posted By : Prof Martin Olivier on 5 Mar 2010, 11:18
Because of other duties I will not be available during my consultation hours slot on Wednesday, 17 March. I will be in my office on Tuesday, 16 March.
Chapters 2 and 3 available
Posted By : Prof Martin Olivier on 5 Mar 2010, 10:34
Chapters 2 and 3 of the prescribed material are now available on netw.co.za. Again, please point out any typographical or other errors to me. I really appreciate any such feedback.
For the class test on Tuesday ensure that you are ready to be tested about the work done during this week's lectures, as well as pages 1-47 in the notes.
For the class test on Tuesday ensure that you are ready to be tested about the work done during this week's lectures, as well as pages 1-47 in the notes.
Cos 212 Semester test clash
Posted By : Mr Francois Mouton on 5 Mar 2010, 09:29
If you had a clash for the previous practical and the cos 212 semester test, you are required to email me directly and also be present at this weeks practical session. Your practical will be marked in this comming practical session. It will only be marked AFTER all the students practical 4 have been marked so be prepared to wait awhile for this.
Marks
Posted By : Mr Francois Mouton on 5 Mar 2010, 09:27
The first draft of the marksheet has been published now. It is your job to make sure that you are included on the list and that your marks are correct and up to date. SCT 3 - 5 will be added as soon as the marksheet has been finalised.
To find your mark you are required to take your student number and mod ( % ) it with 9999. For example if your student number is 27123682 then your mod would be 6394.
If it is the case that your marks are missing or is wrong you are required to let me know before the next practical marking session. Also if you are not on the classlist it is important that you email me about it as soon as possible.
To find your mark you are required to take your student number and mod ( % ) it with 9999. For example if your student number is 27123682 then your mod would be 6394.
If it is the case that your marks are missing or is wrong you are required to let me know before the next practical marking session. Also if you are not on the classlist it is important that you email me about it as soon as possible.
Next chapters will follow RSN
Posted By : Prof Martin Olivier on 1 Mar 2010, 23:33
I had hoped that the next chapters of the prescribed material would have been available over the past weekend. Unfortunately, proofreading is taking longer than planned, and I need another day or so before it will be in a state remotely ready for publishing.
Chapter 1 available
Posted By : Prof Martin Olivier on 16 Feb 2010, 12:21 (last modified on 16 Feb 2010, 12:22)
Draft 1 of Chapter 1 of the prescribed material is now available at netw.co.za. The password to unlock it is 'copyrighted'.
External course site launched
Posted By : Prof Martin Olivier on 2 Feb 2010, 11:31
The course information has been published on http://netw.co.za; it is also available as a tiny zip file, cos332.zip, in the study guide section below.
Study guide available
Posted By : Prof Martin Olivier on 1 Feb 2010, 11:04
The study guide has been posted in the files section below.
Hide Announcement History
Module Content
Study Guide
|
cos332.zip
(24KB) Contents of netw.co.za |
|
guide.pdf
(75KB) Study Guide |
|
marks_cos332.pdf
(180KB) Marksheet |
|
memo.pdf
(78KB) Semester test memorandum |
|
semmark.v0.pdf
(7KB) Semester marks (Version 0) |
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