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When will we be able to sign up for lab sessions for IK2218? Right now it says "Only for students taking EP2120 course!" on the select session pages on moodle.

I may be wrong (or someone changed something in the mean time) but clicking on the link I see "Only for students taking IK2218 course!". Can you confirm it still shows "EP2120" for you?

For me it says "Sorry, this activity is currently hidden" and then redirects to https://moodle.ssvl.kth.se/course/view.php?id=36

Thanks for pointing it out, Daniel!
That's correct -- the activity was hidden (by mistake), but now it should be visible. Sorry for the inconvenience! 

Now the link works for me!

Is the lab1 named as Routing Lab in moodle because the title is UDP and TCP on this page?

Please confirm.

It should be "Labs / Select session for Lab 1 (IK2218)", this is how it appears to me.

Yes, that is for signing up for the lab. I am asking about the name of instruction manual on moodle. Is it the one named as Routing Lab?

No, the manual for the first lab is not titled Routing, nor it is in Moodle. It will appear above.
Routing lab is the fourth lab for EP2120. 

Thanks.

The lab manual for Lab1 is now available above.

Can't seem to find info regarding lab partners. Are we doing the labs in pairs? Should we find a partner before the labs or during?

Regarding the first lab: yes, you are working in pairs.
As for matching: if you have a preferred lab partner, then just ensure that both of you are signed up for the same session. Otherwise, if you do not have a match before coming to the lab, you will be teamed up with another student in the same situation. 

Will there be more sessions for this lab? I realized that I have a seminar during my booked session (B) and there is only one other slot remaining at session F.

We may open another session (during week 40) and there will be a make-up session for those who are unable to attend Lab 1 (IK) or Labs 1/2 (EP) (during week 42). 
However, in order to plan what would be the best solution, I would like to have an estimate of students who do not have their slots booked yet (either because there are no slots left or none of the available options works for them). Please contact me at ljubica@kth.se.

Hello!

I can't register for any  Lab 1 Sessions for IK2218 because they are all full. Have people been registering incorrectly or are there too few sessions?

I am enrolled for the IK2218 Course at Vallhallavägen Campus.

BR,

Marcus

I have also not registered for a lab session, would appreciate another opportunity.

A new session on Monday September 28 (8:00-13:00) has been added! You can sign up now.

In the 4th page of the lab manual, it is written that the report should contain the social security number (personnummer) of each student. What are foreign students without personnummer supposed to do instead?

Those who have temporary personnummer can use that one. Otherwise just leave it blank, it's fine.

There is a redirect loop for the moodle. Am I the only one affected or is this a general problem?

Arne, we are not aware of any issues with the moodle links. If you can provide more specific information, which link you click, what happens, etc, we can have a look.

The loop can be bypassed (at least it was for me) by using a browser that doesn't save cookies such as Chrome incognito mode.

Thanks Marcus. It works. And now it also works again without incognito.

It tried to access the moodle page. I first tried the link I have bookmarked (https://moodle.ssvl.kth.se/course/view.php?id=36) and after that https://moodle.ssvl.kth.se. Neither worked.

Hi, few days ago I cant access the scheduling websites. And yesterday when it works, there are no available slot anymore.

Does anyone have the same experience and still "labless" ?

Today's afternoon session B (starts at 13) is fully booked, yet least crowded of all remaining sessions.
If there are still students without a booking, consider attending this session. Please send me an e-mail if you are intending to do so.

All the labs I'm able to attend are full.
Is there a way to get to carry them through anyway, like showing up at a session (say, the afternoon session of 2015-09-25) anyway? Otherwise, is there anyone I could contact?

Will there perhaps be an extra lab session, since it seems all the current ones are overcrowded?

It is evident that lab sessions sometimes happen to be underutilized.
Please keep in mind that, if you know in advance that you will not be able to attend the lab in your reserved slot (due to schedule collisions or other reasons), there might be other students who would gladly use that opportunity. Thus, you can remove your choice in the booking system and contact the responsible TA to assign you to a different session. Thanks!

When the lab report is sent in, how long does it take before we know if we passed the lab? And how will we get this information?

I will not be able to attend my lab time (25 september 8.00) so if their is anyone who would like to take that spot you are more than welcome to.  

Erika: that's a good question. We will do grading in batches and as soon as your group's report has been graded, we will sent you feedback whether the submission is good as it is (= you passed the lab), or the group needs to make some corrections and resubmit the report (e.g. if some parts are missing or incorrect). That process is iterative but usually does not require many iterations. Feedback will be sent via email, thus to make it more convenient for all of us, it is useful that the person sending the report include other members' emails to reply directly (e.g. in TO/CC field).

Hi, I attended the Mon 21 sep 8:00 - 13:00 lab session, but forgot to write down the email address to submit the report to. Any ideas?

Hi Olof,

I think Ljubica is one of the three TA's. ljubica@kth.se is hers. Please comment me if im wrong.

/satu

Why do you not provide information on how and when the report is to be sent in? Please include it on the lab page or in the lab instructions PDF

As stated at the lab, reports should be submitted by sending an email to any of the lab assistants, within a week from when your group performed the lab exercise.

How are you doing with the gradings for the first labs? It has been almost two weeks since we sent in our report.

I have tentatively scheduled the make-up session for EP2120 labs 1 & 2  and IK2218 lab 1 for Thursday October 15, 2015, starting at 13:00. You can sign up here.
Those who want to perform the make-up lab, but find this proposed schedule inconvenient, should contact me.

Will there be more lab sessions for IK2218 lab 2, apart from the makeup? All sessions are full once more just like with lab 1

The makeup session has plenty of available slots, can you consider that one?

Siraj, i am in The same situation w.r.t lab 2. The makeup lab session page says it's only for lab 1 for IK2218, will there be another makeup session for lab 2 as well?

The makeup session for DNS lab is available here

https://moodle.ssvl.kth.se/mod/choicegroup/view.php?id=2889

One more session is now available for DNS lab:

https://moodle.ssvl.kth.se/mod/choicegroup/view.php?id=2889

How do we know if we passed lab 1?

Is tomorrow's make-up lab session held in room B:230, Q building?

Yes, that's right. We start at 13:00.

(location of the room B:230)

Hi, when will the lab results be reported to the system? Thanks in advance.

Hi,

We are a group of four people who did the 1st lab during the make-up session.

We sent in our lab report after a week to ljubica@kth.se on oct. 22:th. Since then we haven't heard anything back but yesterday we got mails from Daisy saying we will get an F reported to Ladok.

I were under the impression there would be a possibility to re-submit if we failed some part? What did we fail? What can we do to get a passing grade on lab 1?

Pontus,

It turns out that some names were indeed missing in our records and did not get reported correctly. We have taken care of that now, so within a day or so you should be able to see your results.

If the problems remain, please contact your course responsible teacher directly (György or me).

What credentials are we supposed to use to access the course evaluation questionnaire?

Login info should arrive in a mail shortly.

When will the homework be available?

It should be available 1 week before the submission deadline.

Hej, 

Where can we find the subject for Homework 1?
Thanks !

You can now find a link to the assignment above.

Are we supposed to put our name in the submitted solution as well (that is, apart from the name of the document), or keep it hidden to avoid bias for the student grading the solution?

Yes, please put your name in the solution. The grader will be able to see your name, nonetheless, you will not be able to see in the system the name of the one who graded your solution.

I'm having trouble logging in to the homework submission system. The above link immediately prompts a username/password popup dialog. There is no front page, and especially no link to a KTH login page. Please advise.

Please use the username/password provided at the first lecture in the popup. You will then be able to see the front page.

I was unable to make the first lecture due to scheduling issues. The slides from said lecture are also locked behind (presumably) the same login wall. How should I gain access?

A side note - surely I can't be the only participant who missed the first lecture. Is there a system in place to make sure these people get the access they need?

Of course, send me an email.

Regarding

MS Office can export to PDF using the freeware doPDF PDF converter.

I'm using Word 11 for Mac and there is a built-in option to save to PDF from the print window. Maybe there's a similar option for the windows version? Would mean one less installed program. :)

Thanks for the hint.

Hej

Jag har försökt i en halv timme att skicka in min homework men det går inte att logga in.Jag skickar den via mejlet till dig.

MVH Sara

Hi, I cannot upload the file for you, but I can provide you the username/password.

Hej,

What is the process of evaluation of peer's solution?

For example if somebody put 262 144 hosts instead of 262 142 hosts, shall I give him some points or go straight to zero? Feels very subjective for me, because he has some knowledge, but forgot to subtract 2 addresses...

Sounds very subjective to me. Thanks for some recommendations

Grading is not easy...you should try to judge what fraction of the question was answered correctly, and if there is some fundamental error. If there is some explanation, it can help in case the numerical result is bogus or inaccurate. I do not think this should be worth zero.

Hey,

Should we add sticky notes onto the fellow student's solution (of .pdf format) in order to comment on how much points he/she gets and why it worths the given points for each question? Or what would be the preferred way to correct/grade the fellow student's solution? Thanks in advance.

Hi, yes, adding notes to the PDF is a good solution. Creating a new file is good too.

I'm concerned about this grading system - like previous writers, I think it seems fuzzy how a partially incorrect answer should be scored, bordering on completely arbitrary.

For a fictional but plausible example: A largely correct solution to task 2 which does not assign a specific subnet to the H network, in which it might be assumed that the lower-tier routers can handle those routing rules. Would that remove 1 point, or 5 points, or 15? What if this assumption is instead explicitly stated - should that give a full score, since all units are known to be connectable, or still lose some points as a (potentially) sub-optimal solution? 

The complete lack of scoring guidance makes it very difficult to confidently assign a score to my partner's essay, and likewise reduces my confidence in that my own will be graded fairly. Would it be possible to get some guidance on this matter?

Especially since, in Sean's example above, one could also consider it not to be an error.

The task explicitly states that you're supposed to assign a sub-block of the network to networks A-E. It doesn't say that you have to specify the blocks for F-H. As long as they aggregate properly, I think it should give full points, but since the solutions mention the blocks for F-H, I think people might subtract points for not mentioning them.

Hej,

I just tried to add my review in the homework submission system and I can't upload it " No documents checked out to you ". Is there a problem or something with the submission system? 

I've just uploaded  my review in the homework submission  but the problem is that when I open it I can not see my comment !!!!!!!!!!! What should I do?

@Pierre: Please "check out" the original file, then you can "check in" the reviewed file.

@Maliheh: "check out" the file again, and verify that you can see the comments. Then "check in" a version on which you can see the comments.

Perfect working fine now! Tack !

Tack.

@Erik & Sean: Grading is indeed not an easy task, one needs to carefully assess what fraction of the answer is correct, whether there is some fundamental mistake, etc. We do not provide detailed instructions on how to grade, but hope that you can make an informed judgement based on your understanding of the problem and of the solutions. This is an important part of the learning process, as you will have to understand the material fairly well to be able to assess the value of a partially correct solution.

About grading: with peer reviewing there will always be differences in the grading, we are fully aware of that. Should you end up in the situation that you don't have enough points to take the exam, and you feel that you haven't received a fair grading, you should contact the teachers and we will review the grading. We will only do it in those cases, though. Keep in mind that the purpose of the home assignments is that you should learn, not to prevent students from taking the exam.

I should add that in practice, this has rarely been a problem.

In homework two, question three, part c, we are asked to name the interfaces on which messages are sent. But the topographical sketch doesn't seem to supply these. Are we supposed to make up interfaces or can we just use the IP-addresses?

Furthermore, when building routing tables, are we to use made up interfaces or can we use IP-adresses here as well?

You can make up interface names, just make sure you give a definition. You can also use North, South, East, West.

Re 2nd part of your question: the figure contains the IP addresses (.1, .2,...).

In the solutions for homework two it says for the very last exercise that "Missing the transmission time (2 ms) is a mistake." What does the transmission time refer to?

Also, in my hand-in I used an MSS of 536 since that's the default TCP value - is it always assumed that the path MTU is used for MSS? I don't think that's obvious at all. The problem is that it propagates to the rest of the TCP questions and I, although I'm biased, don't think that it should result in a total deduction of all points in the follow-up questions, even if the answers are essentially wrong. What's your stand on this? 

There is a problem with the submission system, when somebody used accented letters in the name of the file. After the check-in of review in the system there follows the error message

"Error: wrong file! Please check in the right file."

This happens even when the correct (the same) name is used as in the original name of the pdf. How can I fix this in order to being able to upload the review?

I have a question about the grading on the solution for question 3c, Routing. If the student has written that A send one message each to the neighbours B, D and E and in that case sent the same vectors to both B and D, and another one to E (with the infinity number). According to the solution the same message with the infinity number is sent to D and E. I have a hard time grading this solution since I am not sure how "big" this mistake is.

And also, when will the next homework be out? It is due next wednesday.

@Matej: Yes, accented letters are complicated, as they may have different codes on different systems. This is why we asked "Please avoid using accented letters in the file name.". pls send me a mail.

@Erika: According to RFC 2453 routers would use multicast on multicast/broadcast capable networks, like Ethernet, but you can configure most RIPv2 routers to use unicast.

@Fredrik: Transmission time is the time need to transmit a packet (send the bits).

If the path MTU is known then you would set the MSS based on that, as it allows higher throughput.

Is the transmission time something that should've been defined in the question or something that we were to figure out by ourselves somehow (e.g. by calculating it from the given data)?

Sure, that makes a lot of sense. Is it the de jure way, i.e. is it always done like that? Can I read up on it in the course book or somewhere online?  Sorry for being so inquisitive. :)

Hello.

I was wondering when the next homework will be uploaded. I was planning on doing it today or at the latest tomorrow as I have problems finding time for it afterwards. So I was hoping you would upload it soon.

Can you tell me when it will be uploaded so that I can plan better?

Thanks!

You could calculate the transmission time based on the given data.

The book does not say much about setting the MSS, other than based on the IPv4 reqs. There is quite some info available online though (e.g., Cisco has many pages dealing with MSS and PMTUD).

We plan to open homework number three in an hour or two. Sorry for the delay.

Homework 3 is now available.

(Homework 3) 
Exactly why do we need to study header fields not discussed in the
textbook for question 3f? Do you seek any specific header
fields attached in the reply/request, or whats the deal here? :)

2. (minor question). In question 3.e, shall we assume that the
tcp connection must be terminated properly using 3/4 way terminating
handshakes before the page is fully loaded?

Jack,

Question 3f: Yes, there are header fields that are relevant for the proxy. They shouldn't be too hard to spot. The book's coverage of proxy servers is a bit simplistic, so we want you to first study the basics of a proxy in the book, and then use the Internet to learn a little more about about proxies in practice. 

Question 3e: You can ignore the time it takes to terminate the connection. The grading guidelines (which you of course haven't seen yet) say that either way is fine. 

I thought those fields are related to client-side caching by the browser rather than by the proxy server. Is that a misunderstanding?

Fredrik,

Without being too specific, I wouldn't say that cache-related fields concern the client only. On the contrary, cache directives are intended for controlling intermediate caches between client and server. 

Peter,

Okay, thanks! I will re-evaluate my answers and try to be more thorough.

Regarding question 3(d) in Homework 3 - Should we solve it using the sequential approach or the parallel approach ?

Surya,

For 3d in homework 3, any legal behavior is fine. As long as you can argue that your solution is valid according to HTTP, given the information in the problem, the solution is acceptable.

There was a question for clarification of 1b in homework 3. The question is straight-forward: you should describe the communication in the problem using the vocabulary "connection-oriented", "concurrent", "connectionless", and "iterative".

Is the solution for homework 3 incorrect for question 3a? It says the answer is https:/www.opera.org:9821/claypool . I'm not sure where that port number comes from.

Erik,

The correct port number for hw 3, question 3a, should be 1935. I have updated the solutions. 

Hej!

I'm grading my partner's homework number 3 and I seek consultation regarding question 3.a

The student answered shortly, http://www.opera.org/claypool. Since the student missed the port in the URL, any points should be deducted for this? 

In addition to Ahmad's question, should you deduct points for a missing "http://" ? Since both http and https are accepted answers and http is usually implied when writing urls.

About grading for hw3, question 3a: Deduct one point for every missing or incorrect component of the URL. 

It seems that the person grading my submission of HW3 skipped the second half and by doing so he/she gives me (probably) fewer points than what I should have been given.

Will I have to do the make-up assignment because of this?

Fabin, 

Too bad that your entire submission wasn't graded.

The usual policy applies: After the 4th homework, if you don't have enough points and feel that you haven't received a fair grading, you can contact the teachers and we will look into it.

I seem to be unable to download the solution pdf. I get the error message ERR_TOO_MANY_REDIRECTS.

Martin,

By mistake I responded as a new post, it should have been as a comment to the Homework page. I submit it again, so it ends up in the right place.

If you get too many redirects, there are a few things you could try:

- Clear the cache in the browser

- Open a private or incognito browser window

- Erase your browser cookies (or install a fresh copy of some other browser)

Thank you for the response.

About solution for question 3d, The client would know about the 5 images only after it receives the main page. So would it be possible to send requests for the images along with the request for the main page when requesting in parallel (as in the solution)? Shouldn't the requests for the images be send only after the main page is received?

Quarter past 5 and still no grade for my homework, what's the procedure about that?

If your fellow student fails to grade your submission then we do it instead. You will see your points as soon as it is done.

Vishnu,

You are absolutely right! Getting the main page takes an RTT, so 5 RTTs total. Solutions updated.

As a side note, HTTP/2 introduces "Server Push" to avoid this extra RTT.

Hai 

Are we able to claim for the points for 3d if our solution is correct according to updated solutions.

Thank you.

Lakshmi.

Is the 4th homework submission 8th of October or is it a misprint? Usually it has been every Wednesday.

No. They added an extra day since the lecture on Wednesday is related to the homework, so we will get an extra day to hand it in. 

The last lecture is actually on Thursday 13-15 according to schedule. So it seems rather unrealistic to have the homework deadline two hours later. Are we supposed to only have these two hours for doing the part of the homework related to the last lecture (Firewalls and NAT)? Surely something must be wrong?

Daniel, 

We explained at the introduction that it might happen at a few occasions that there is little time between a lecture and the homework deadline.

The slides from the lecture will be available very soon, so you can study them in advance. They should give some guidance for solving the home assignment.

Hi,

the lecture notes for tomorrow's lecture on IP gateways are now available.

Best regards,
Markus

Hi,

I am just wondering when will the Make-up Homework be posted since it is already due (a little) less than a week from now.

Thanks,

Sharbel

Homework 5 is now available. It is an opportunity to make up if you did not get sufficiently many points on the first four homeworks.  

Are the points on homework 5 added to the total score, or is it judged independently?

They are added to the total.

Why the score of my 4th homework bocame 77, it's wrong.

Some guy's all four homeworks score bocame 77. What's going on?

It should be correct now, please let me know if not. All others' have been restored to the original values as well.

Solution for homework 4 contains the answer for a question 2d) while the homework doesn't even have a d) question on 2. In addition, the "solution" for 2d) is literally the same as 2b). Is this just a mistake that we should ignore?

Hi,

solution 2b) was duplicated by mistake and ended up also as solution 2d) (so you can just ignore it). I have uploaded a new version without the duplicate now.

Regards,
Markus

The make-up lab task 4 starts at c) and ends at e), I guess that's an error?

In Homework 5, Question 2)a

The datagram is delivered to Host H3 or H4 ? as it's mentioned before that it should be to host H4 

Unfortunately there were some small errors in homework 5. We have uploaded a corrected version. 

The errors were in questions 2 and 4. The corrections are clearly marked so you can easily see what has changed.

As Ehab points out question 2a) still claims that a datagram is delivered to H3, even though you switch the recipient to H4 in 2b), is it an error?

It should be H4 in 2a as well. There is only 1 datagram being delivered (from H5 to H4).

If we already have 300 points, the 5th one is optional right ? 

Yes.

thank you 

When can I sign up for lab1?

And do I need to join a group?

Above you can find the links for signing up for labs 1 and 2. Then for each lab choose one of the sessions that works for you. If you do not already have a preferred lab partner, you will be matched with another student in the lab. I hope this answers your questions.

The links does not work

Have you enrolled yourself to this course in Moodle?

Hi, I have joined the following session for lab1, if you want to work with me, please join this lab.

EP2120 Lab 1 Session B 2015-09-18 13:00-18:00

Hi all,

Since available lab sessions are utilized by DNS lab, I would like to book two more routing lab sessions on 14th of October (08:13- 13:18) for EP2120 students. Please let me know if it is not suitable for you (e.g.  clash with any other course you are taking).

Best Regards,

Siraj

Hi All,

Booking for  EP2120 Routing lab is now open. It is mandatory to prepare and answer lab questions before the lab as it is also very useful during the lab.

Regards,

Siraj

I have tentatively scheduled the make-up session for labs 1 & 2 for Thursday October 15, 2015, starting at 13:00. You can sign up here.
Those who want to perform the make-up lab, but find this proposed schedule inconvenient, should contact me.

The makeup session for DNS lab is available here

https://moodle.ssvl.kth.se/mod/choicegroup/view.php?id=2889

One more session is now available for DNS lab:

https://moodle.ssvl.kth.se/mod/choicegroup/view.php?id=2889

Hello, I am wondering is that mandatory for every student?

Hi, the project is for bonus points and is voluntary.

tack

Anyone want to make group for this bonus group project? We still have time to submit proposal

hi

     I am also interested for bonus group project. kinldy email me if you are still looking at muhsa@kth.se

Could u please give us access to the optional materials too? It will also be helpful!