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Posted by SCag 
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avatar Exam feedback
January 30, 2012 10:47AM
So, I got annoyed about having to spend my reading time filling in the front cover and attendance sheet.

Anycow, while paging to the back to get to the attendance, I glossed over the written questions. And a smile came. The exam was identical to the past paper, errors and all.
I made myself a worked solution for the past paper yesterday, so I knew what to do for every question ^_^
A lot of the MPC questions(and some of the written ones, such as the SCTP data chunk last fragment) were designed to trick us (such as triangle crossing and double routing. Its meant to be triangle routing and double crossing).

I also felt there wasnt enough space provided to write the written questions.

Now, regarding errors (in the MPC section):
Question 24: While looking for the answer in my textbook, A,B and C are all found word for word (meaning true). D is a trick, its SYN flooding, not ACK flooding. But there is no option A,B,C.

Question 48: This is more of a trick. But I am not sure about it. It refers to two hosts that communicate using IPv6, but along the way it goes through an IPv4 router. Word for word, this description matches tunneling in the text book. But cant tunneling or header translation both be used? In tunnelings case, the IPv4 is bypassed with the tunnel. In header translation (although meant for a receiver using IPv4), translates the IPv6 header into IPv4, so it will go through the IPv4 router and still get delivered correctly(IPv6 can still read IPv4 headers). The answer to an equivalent question in assignment 4, was also wrong in the solutions (does the lecturer know, or will this error continue into the exam?)
Re: Exam feedback
January 30, 2012 11:16AM
I cudn't stop smiling after opening the exam question paper smiling smiley

-Q24, I chose A, even though A, B and C were right...
-Q48, I went for tunneling
-and FSD diagram - no mention of state D or event 5

oh well smile wish I could've walked out after half an hour, had to sit for 30min doodling and making sure I coloured in the mcq answer sheet correctly...
avatar Re: Exam feedback
January 30, 2012 12:07PM
I chose B (both b and c) for question 24, because I confirmed both of those word for word in the textbook while preparing for the exam. The picture I also knew to be correct, but decided against A only because two thirds of B were correct, and also I thought maybe one word or rwnd or something like that has been changed from the book, making it wrong.

I answered the same as you for question 48.

As for the FSM, it was a general FSM. So if you have done a subject like COS301, its a cake walk. To be honest, I dont know why they put a generic FSM in the exam, its not really relevant how a FSM works. The only relevant thing to do with a FSM is to draw the FSM for stop-and-wait (for example). I dont know why they didnt ask that instead.
Re: Exam feedback
January 30, 2012 06:32PM
Jerr I thought I was going crazy over Question 24, decided to go with both b and c too, Question 48 I went with Tunneling, that Double Routing, Triangle Crossing thingy stumped me, my eyes were seeing Triangle Routing and Double Crossing since I started studying last week and only today when I got home and went through the old paper again did i see, flip (but hey, at least its only one mark), anyways seems like UNISA is trying their best to give me my degreegrinning smiley, one last year............and to think last week I was considering not writing and also that I nearly missed the exam because of morning traffic in R80-DF Malan (PTA), I can only be glad i made it smiling smiley, what are you guys taking this year? I am doing Software Project Management only, de-registered it last because it was moer se lot
avatar Re: Exam feedback
January 30, 2012 09:12PM
There were STACKS of tricks hidden in the paper. Two others were: Q50 in the multiple choice. At a glance, they all look correct. But if you read A closely, it says "This protocol requires a physical connection", physical is meant to be logical. The SCTP data chunk question asked you to write down which was the last data chunk. But there wasnt a last data chunk (BE 01).

As for subjects, I wrote all 10 honours exams this exam period (my last one is software project management coming this thursday).

The question is, what do we do about Q24? Do we forget about it because its only 1 mark, or do we raise the question with the lecturer?
Re: Exam feedback
January 31, 2012 03:37PM
@Scaq: I dropped him an email yesterday about Question 24, will wait and see if he responds! As for question 50, "...at the IP Level" gave it up for me and I went for b and c, I think the correct is Network or Transport Level i cant remember.................the long questions I don't think I got anything wrong smiling bouncing smiley, except that question 8, which I had already convinced myself that if its in the exam, its 8 marks I am willing to lose, this is Computer Science not So you think you can draw!lol....you got GUTS boet, 10 subjects?#flip, I am left with Soft Project Management, and that's if I didn't flunk Info Sec, which I think I did sad smiley
avatar Re: Exam feedback
January 31, 2012 06:03PM

except that question 8, which I had already convinced myself that if its in the exam, its 8 marks I am willing to lose
But it was so easy :< If you went over the material you would have seen FSMs often, all you had to know was that you draw a circle for the state, with its name inside. Then an arrow to the next state with a label showing the event and action that occurs to move to the next state :< 8 marks for free. I drew it based on what I remembered from drawing FSMs in COS301 in third year.


this is Computer Science not So you think you can draw!
Finite state machines are a massive part of theoretical computer science. More like, "This is networking, not computer science" tongue sticking out smiley

As already mentioned, drawing a generic FSM isnt really relevant to networking. They should have asked us to draw an FSM for connection establishment, or something like that. Then I would have been screwed :|
Re: Exam feedback
January 31, 2012 08:55PM
Thing is, the only reason I did Computer Networks was because I didn't wanna do Human Computer Interaction, I did my degree with UFS so Networking was a first topic (They do it at Hons level) so I am actually not a networking person (I actually started studying it last week Thursday after a friend convinced me to write the exam smiling smiley), so I figured, its not like I am gon have to use FSMs anytime soon and just browsed it, I'm firmly a database person, with a love for Security, think Info Sec would be my next destination Masters wise.....but if I don't get a distinction I am doing a sit in in the lecture's office until he gives me my distinction, that paper was irritatingly easy since I had prepared my own memogrinning smiley.....anyways Gudluck with INF425N on Thursday boetsmile
Re: Exam feedback
January 31, 2012 08:58PM
On FSMs, the last time I had to do that was in 3rd year Software Engineering in 2004, I just hate drawing period, nah make that I HATE DOCUMENTING!cool smiley
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