ADVANTAGES AND DISADVANTAGES OF TCP AND UDP

since, rhea talked about TCP, i would like to throw some light on the advantages and disadvantages of TCP and UDP.

I have only included those points which i could understand after reading . there are loads of points available on google on the advantages and disadvantages of TCP and UDP which you could refer. 

ADVANTAGES OF TCP

(1) TCP always guarantees three things - your data reaches its destination,it reaches there in time and it reaches    there without duplication.

(2) in TCP, since all the work is done by the operating system, so you just need to sit back and watch the show. Even the debugging is taken care of by your OS.

(3) It automatically breaks up data into packets for you.

(4) It is slower in functioning than UDP

DISADVANTAGES OF TCP

(1) since, all the work is being done by your OS, so if there are bugs in your OS, then you will face many problems like problems in surfing and downloading contents from the net.

(2) TCP cannot be used for broadcast and multicast connections.

ADVANTAGES OF UDP

(1) Broadcast and multicast connections are available with UDP which is not the case with TCP.

(2) It does not restrict you to connection based communication model

(3) Much faster than TCP

DISADVANTAGES OF UDP

(1) There are no guarantees with UDP. It is possible that a packet may not be delivered, or delivered twice, or delivered not in time.  

(2) you have to manually break the data into packets


Comments are always welcome :)

WHAT IS A PROTOCOL? (Focus on TCP/IP)

Hi everyone

I was trying to understand the meaning of 'protocol' and the use of TCP/IP with the help of our all-time friend Google. I thought I would write in a blog about the same to save my friends' time searching!

(Just as for most of us, this is my first blog too!)

From all my search on Google, I gathered that:

A protocol is a formal description of message formats and the rules that two or more machines must follow to exchange those messages.

For instance, if two people A & B want to communicate. Imagine the confusion and chaos if they start talking simultaneously. To avoid it, they must follow a set of rules while talking, as to who talks first and for how long etc. This common set of rules would be known as communication protocol for A & B.

Now, there are various protocols used in various types of networks.

TCP/IP is the native protocol of Internet.

These are two separate protocols.

-> TCP (Transmission Control Protocol) deals with the construction of data packets.

(A packet is a sequence of bytes and consists of a header and a body. The header describes the packet's destination and the body contains the data being transmitted.)

->IP routes them from machine to machine.

More technically, TCP provides the service of exchanging data reliably between two network hosts; on the other hand, IP handles addressing and routing messages across one or more networks.

So basically, TCP provides a communication service at an intermediate level between an application program and the Internet Protocol (IP).

-> Basic function of TCP

That is, when an application program desires to send a large chunk of data across the internet using IP, the data has to be broken into IP-sized pieces and then a series of IP requests have to be issued. Here, TCP comes to the rescue. Instead of issuing several requests, the software can issue a single request to TCP and let TCP handle the IP details.

-> Error detection during transfer of data packets

Now, due to network congestion or other unpredictable network behaviour, IP packets can be lost, duplicated or delivered out of order. TCP detects these problems, requests retransmission of lost packets, rearranges out of order packets and even helps reduce network congestion. Once the TCP receiver has finally reassembled a perfect copy of the original message, it passes it to the application program.

Thus, the basic function of the TCP layer is to abstract (recall the concept of Data hiding and abstraction we have studied in programming :D) application's communication from the underlying network details.

->TCP: Accurate delivery rather than timely delivery

TCP guarantees accurate delivery of a data stream from one host to another, i.e., without duplication or loss of data. But it does incur relatively long time delays, for example, while waiting for retransmission of lost messages.

Thus, though it ensures delivery of complete messages, it is not particularly suitable for real-time applications such as Voice over IP. (There are other protocols for such applications, like RTP - Real Transfer Protocol)

AT A GLANCE:

Suppose an HTML file has to transferred across the web. The TCP divides the data into segments and then, forwards them individually to the IP layer. Now, this layer encapsulates each segment into an IP packet, and adds a header containing the destination IP address. Note that even though each packet has the same destination address, they can be routed on different paths through the network. When the segments reach the destination computer, the TCP layer reassembles them and ensures that they are correctly ordered and error free, before streaming them into an application.

I hope this post will help you all!

Any suggestions and comments are always welcome! :)

My Experience Leading Lab Session 3

Even though I didn't have a very challenging topic (Installing Multiple OS), it was very difficult to prepare enough to make sure that I could explain the topic to other students. It took me about 2 hours to prepare for the lab session (I didn't attend the training session), but I didn't know that we weren't going to cover all the methods of installation.

The lab session turned to be surprisingly easy to handle. The teaching assistants occassionally gave some input to us about how we should handle the class. The class didn't misbehave much (mainly because they were afraid of us giving them a bad evaluation when it was their turn to lead :P), and the lab session went along smoothly.

It was great using QEMU and VirtualBox, but I found myself wishing that we could use VMWare Player too. It would also have been nice to have been able to install a version of Windows as a virtual machine.

Personally, I thought that Lab Session 3 was one of the most useful lab sessions because almost everyone used the knowledge they gained during the session later, installing a Linux - based operating system.

leading the lab session (stepping into shoes that were one size too big for me :D)

Hey everyone ! like Karan this is also my first blog on IIIT-D:Systems Management.Enjoy reading about my experience of leading the lab session-3 :)

Well in the first class itself Sir had said that he wanted the lab sessions to be led by students and he also said that it would be better if people come forward to lead the lab sessions and get over with it quickly :)

When Sir announced in class that he needed names of students who were interested in leading Lab session-3 me and Ujjwal thought why not get over with it right now itself. Moreover with the topic of the lab session being 'Installing multiple OS' we thought it would be good to know about it and that would help us in installing Ubuntu on our own systems as well.

We had our training session on Saturday(7th of August) under Arjun. Now let me tell you Arjun was like so well prepared for the training session. I did not know that there were so many ways of installing a OS. Native installation , Virtual installation, VMWare, VirtualBox all these these things were new for me and some of the things went over the head too. But when we finally did things on our own later in the day we felt better but the QEMU part still puzzled me. Then i went home and searched You Tube for installation guides, researched some parts on Wikipedia and got to know new things.

And then started a really tight week with assignments, homework's to be submitted (finally realised why seniors had been mentioning all along that you don't rest at IIIT :) ) . Anyways both me and Ujjwal were very nervous (in fact both of us did not play TT and pool respectively that day during the break). But when things began we started becoming confident and things passed off without any major glitches. I really have to thank Group 4 because they were really understanding of the situation and were really supportive even when things did not actually go according to plan(never does as Karan pointed out).

And i would also like to take this opportunity to thank Ujjwal who is a really good partner.

At the end of the session I just felt that its not an easy job standing at the front of the class and making everyone listen to you and follow your instructions. Also that it does take a lot of preparation to be able to do that and I think that i was definitely not a 100% prepared. I could not answer some questions that were asked by my STUDENTS :p And I thought I would just tell them to write a blog on the very questions they asked :P but the fact was that I felt bad at not having been able to answer there question.

Nevertheless I thoroughly enjoyed it and felt like I had done a ok job that definitely called for a brownie treat for myself from Nescafe's :D

Given a chance to lead the lab session again I would definitely do it and that time hopefully I would be much better prepared having gained some valuable experience :) Because although a tough job it does bring a sense of responsibility on our shoulders and also puts us in command :)

Thank you :)

My experience of leading a lab session

Hey everyone! So this is my first blog post on the IIITD : System Management blog. I will be sharing with you my experience of leading a lab session! I hope you do like it.


I along with my partner Manik turned up for the training on 14th Aug 2010. I was actually late for it because the previous day we had our Freshers Party and that had left me completely tired. Samy sir took our training that day. And I must say he was pretty well prepared for it. He knew almost all the questions that I asked him. We were actually present in the lab for 4 hours barring a 5 mins break in between. And our training wasn't even complete then. We only managed to cover the Windows part. The Linux part was yet to be covered. At the end of the training there was one thing of which I was sure of, 'A huge task lay ahead of me!'.


I sat down with Manik on monday and divided the sub-topics between us. We took alternative topics so that none of us would be speaking for a longer time. We researched a bit 'Wikipedia' and noted down the things that we felt important and should be told to the class. We decided that while one of us would be explaining the topic to the class, the other would be going personally to everyone, asking them their doubts and clarifying if any. So that no one feels left out and everyone is happy with our performance. :P
The main problem that we faced was how to finish a lab session in 1.5 hrs when the training itself took 4 hours. Samy sir had told us that he would be teaching Linux to the class in the last 0.5 hr. 


The day eventually came. And I can't even tell you how nervous I was before it. I had butterflies in my stomach and my face completely reflected the state of my mind at that time. The group 2 people can actually vouch for this! But somehow I suppose, I did manage it. ;)


I started off with proceedings and Manik took on from me really well. It didn't go as planned. Well now I have actually started to believe that nothing in life goes according to plan! But it still went pretty well, I suppose. :P 
We started off as we had decided. The process was quite smooth except for a few hiccups! We did face a few problems, but we dealt with them with ease. The group 2 people were really helpful. They weren't asking much tricky questions. Well, I guess that was due to the fact that their turn was yet to come. But on the whole, they were quite understanding and sympathetic with me! :P 
And before we knew it, we were over with it! :D

They basically had 2 complaints from us. Firstly that we weren't able to finish the lab before 4 p.m.! And secondly that this was the most boring lab session! The first one I accept was in our hands. But the second wasn't! :P 


At the end of the session, I actually felt that I was a bit less prepared. I couldn't answer a few questions that my friends asked. I had to eventually say that I didn't know that and I would have to look that up. And I didn't at all like saying that. :|


To conclude, I would like to say that leading the lab session was good experience. You don't really get to step into your teacher's shoes everyday. I thoroughly enjoyed the leading part, although not the training and the part before it! :P 
But it was nevertheless a good experience. Something which I would surely like to experience again! :)

A La-b-log....

It was 10^th of August, 2010 when we guys (me and Kshitiz) had to lead the SM Lab Session. Our group was the one who was the first sub leading group among the whole 2010 batch. Once we gave our names for the same, then only we started realizing that “Kya hoga hamara!”. No experience and had not seen any of the leading groups before as we were the first ones. But with the name of God, we finally decided “Jo bhi hoga, karna to padega...”.

Training session was scheduled on the preceding Saturday (i.e.7^th August, 2010). After the training session, I was especially in a complete messy state because Kshitiz had done a bit of all these before but if you talk about me, I was a beginner to all these stuff. But when we started doing all those on our own then ”Jaan mein jaan ayi!”. Yes, we would also be able to do something.

Those 3-4 days were pretty hectic for us. We had to submit few assignments, a test was scheduled and this task of leading the lab session. Finally, the day came and everything went really good. And finally we both were like ”Ah! Finally everyone installed it!”. Everyone left happily but the worst part was that we both had to spent another 1-1.5 hour to uninstall the OS from all the systems. Rest, everything was like a new experience for both of us. It feels great to be in the place of teachers for sometime but on the other side you start realizing that how much effort teachers have to put in to make us understand.

Kshitiz would like me to add here, that being in the teachers shoes was a completely new experience, it was great. But when I ask him would you want to do it again? Silence...

Thank you! :)

Experience of leading lab session-3

Hey everyone!! Its been quite some time I lead Lab Session-3 ( Linux installation)... But I guess its never too late to share experiences...

Let me start with the training part. We reached for training on Saturday around 2:30 pm. And it continued till 6:30 in evening. For the first 2 hours, we were just staring at Arjun (our TA) trying to figure out what he was doing! Finally when we started doing on our own, we got it.

I was so tensed before the lab session. What all are my group mates going to ask? What if I cant answer? And after the lab session was over, i was laughing at whatever happened. It was a mixed experience. On one hand, I felt everything became chaotic. We (me n my partner, Monika) had to go to each table since everyone had reached to different steps. Plus, I felt we should have been a bit more prepared. On the other hand, was happy to see that ultimately everyone had installed linux natively and using virtual machines.
Lab finished in around 1.5 hrs. But that was for others. We had to stay back to uninstall linux now so that other groups can perform lab next day. So we stayed back till around 6:30 pm.
I learnt a very important thing through this process, that its easy to learn something. But to teach that to others, is really tough. But overall a very nice & enriching experience!! :)