Advance Computer Networks : [BE-IT] Elective

Advance Computer Networks

Unit I Introduction

Requirements , Network architecture , Networking principles, Network services and Layered architecture , Network services and Layered architecture , Future networks ( Internet , ATM , Cable TV, Wireless – Bluetooth, Wi-Fi, WiMax, Cell phone )

Unit II Advanced Technologies

Virtual circuits, Fixed size packets, Small size packets, Integrated service, History, Challenges, ATM Network protocols, IP over ATM, Wireless networks : Wireless communication basics, architecture, mobility management, wireless network protocols. Ad-hoc networks Basic concepts, routing; Bluetooth

(802.15.1), Wi-Fi (802.11), WiMAX (802.16), Optical Network : links, WDM system, Optical LANs, Optical paths and networks.

Unit III Performance of Networks

Control of networks: objectives and methods of control, Circuit switched networks, Datagram and ATM networks. Mathematical background for control of networks like Circuit switched networks, Datagram and ATM networks

Unit IV Advanced Routing - I

Routing architecture , Routing between peers ( BGP) , IP switching and Multi- Protocol Label Switching (MPLS), MPLS Architecture and related protocols , Traffic Engineering (TE) and TE with MPLS , NAT and Virtual Private Networks (L2, L3, and Hybrid), CIDR –Introduction , CIDR addressing, CIDR

address blocks and Bit masks

Unit V Advanced Routing - II

Mobile IP- characteristics, Mobile IP operation, Security related issues. Mobility in networks. Voice and Video over IP (RTP, RSVP, QoS) IPv6: Why IPv6, basic protocol, extensions and options, support for QoS, security, etc., neighbor discovery, auto-configuration, routing. Changes to other protocols. Application

Programming Interface for IPv6.

Unit VI Ad Hoc Networking

An Introduction, A DoD Perspective on Mobile Ad Hoc Networks, DSDV: Routing over a Multihop Wireless Network of Mobile Computers, Cluster-Based Networks, DSR: The Dynamic Source Routing Protocol for Multihop Wireless Ad Hoc Networks

Download Books

Computer Networks: A Systems Approach

Larry L. Peterson, Bruce S

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Internetworking with TCP/IP

Douglas E. Comer

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IPV4 and IPV6 : A short Explanation with Animation

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Before we start, let us clear the most essential term for this article : IP

IP- stands for Internet Protocol. It is only because of IP, that we are now able to connect with each other on a network. Now, basically why do we need an IP address to connect on the network? Let us consider a small example, suppose you are away from your hometown and your friends and family would like to reach you through any means of communication like cellphone, letters, emails or post cards , then the first and foremost thing you need to have an address. An address then allows you to be recognized over a network or a region. The above picture will make sense, when you try contacting someone with some means of communication ,say a simple traditional letter or postcard. Here, you need to provide an address, so that your letter will be delivered.

  Eg:

          To,
               Mr. XYZ,
               23/411,  East Street, Bronx ,
               NewYork, USA

 This is a simple traditional address which allows you or a particular person or an organization to be recognized universally.

     In the same way, when you connect to any particular network, the data sent can reach the destination only if it has a particular address or unique end point. This is where , IP plays the role of savior. Every node or peer on a network in the world is uniquely identified by an address, this address is called the IP address. The IP address is a 32 bit address, which means it can have 2 to the power 32 different combinations of addresses,which provides a huge pool for IP addresses.

    So in simple words, we define IP address as : a numerical label assigned to each device (eg: Computer,Printer) participating in the computer network and uses Internet Protocol for communication.

So what is IPV4?

      IPv4 stands for Internet Protocol version 4. It is basically the underlying technology that makes it possible for us to connect our devices to the web. Whenever a device like a computer or a printer try to access the Internet , it is assigned a unique, numerical IP address such as 128.119.213.227. 

    Without IP addresses, computers would not be able to communicate and send data to each other. It’s essential to the infrastructure of the web.

What is IPv6?
Here is a short animation which explores deep into the IPV6, Hit the play button
                             

   IPv6 is the sixth revision to the Internet Protocol and the successor to IPv4. It functions similarly to IPv4 in that it provides the unique, numerical IP addresses necessary for Internet-enabled devices to communicate. However, it does sport one major difference: it utilizes 128-bit addresses.

What is the reason that we are moving away from IPV4 to IPV6?

    The Internet has run out of Internet addresses, sort of.Everyday,more and more number of devices are getting attached to the network and hence more and more addresses have to be allocated to the corresponding new devices. Perhaps you’ve heard the news: the last blocks of IPv4 Internet addresses have been allocated. The fundamental underlying technology that has powered Internet Protocol addresses since the Internet’s inceptionwill soon be exhausted.

A new technology will take its place, though. IPv4′s successor is IPv6, a system that will not only offer far more numerical addresses, but will simplify address assignments and additional network security features.

Q: How does IPv6 solve this problem?

   As previously stated, IPv6 utilizes 128-bit Internet addresses. Therefore, it can support 2^128 Internet addresses — 340,282,366,920,938,000,000,000,000,000,000,000,000 of them to be exact. That’s a lot of addresses, so many that it requires a hexadecimal system to display the addresses. In other words, there are more than enough IPv6 addresses to keep the Internet operational for a very, very long time.

Q: So why don’t we just switch?

   The depletion of IPv4 addresses was predicted years ago, so the switch has been in progress for the last decade. However, progress has been slow — only a small fraction of the web has switched over to the new protocol. In addition, IPv4 and IPv6 essentially run as parallel networks — exchanging data between these protocols requires special gateways.

To make the switch, software and routers will have to be changed to support the more advanced network. This will take time and money.

Q: How will this affect me?

    Initially, it won’t have a major impact on your life. Most operating systems actually support IPv6, including Mac OS X 10.2 and Windows XP SP 1. However, many routers and servers don’t support it, making a connection between a device with an IPv6 address to a router or server that only supports IPv4 impossible. IPv6 is also still in its infancy; it has a lot of bugs and security issues that still need to be fixed, which could result in one giant mess.  

  Nobody’s sure how much the transition will cost or how long it will take, but it has to be done in order for the web to function as it does today.

-x-x--x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-

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Pune University : TE - IT - 2010 Dec : Question Papers

Question Papers for Third Year Engineering  in
 Information Technology :Pune University
     

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Software Engineering	Download Now
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AES Algorithm : Explanation with Animation

       AES algorithm is the advanced encryption standard form of algorithm which had been used as a symmetric form of encryption.  This form of algorithm is being used by the government of United States in various applications. The AES algorithm it can be seen that three different type of black ciphers exist and each of them is being used to perform different activities. The three types of AES algorithm are AES192, AES-128 and AES-256.  Each of the black cipher had been used for the purpose of having some sort of color bit which is mainly being used as a block size with the combination of several keys and other tools with them.

     The AES algorithms have become so famous that they are being used by most of the people at any time and hence it is widely being used. They are found to be quite helpful to the people and it had also been linked with the data encryption method too. It had been found out that the 128 bits block size is the fixed size of block that is being used by many people.  Moreover substitution permutation network is the only system which is being used in the AES algorithm and it had also been used for the purpose of developing some of the designs as well.


    AES algorithm is also supported to be used by the state which had been built in the form of a 4*4 size. On the other hand the cipher text which is contained in the AES algorithm can also be used as a mean of generating some level of output by providing some amount of input to it. Different types of steps had also been developed for the purpose of arriving at the AES algorithm and each step is responsible for performing some of the tasks.


 Learn How the AES Algorithm works .. using this Animation :

  (keep pressing Enter to keep advancing)

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Selective Repeat Protocol Video

      A sliding window protocol is a feature of packet-based data transmission protocols. Sliding window protocols are used where reliable in-order delivery of packets is required, such as in the Data Link Layer (OSI model) as well as in the Transmission Control Protocol (TCP).

          Conceptually, each portion of the transmission (packets in most data link layers, but bytes in TCP) is assigned a unique consecutive sequence number, and the receiver uses the numbers to place received packets in the correct order, discarding duplicate packets and identifying missing ones. The problem with this is that there is no limit of the size of the sequence numbers that can be required.

By placing limits on the number of packets that can be transmitted or received at any given time, a sliding window protocol allows an unlimited number of packets to be communicated using fixed-size sequence numbers.

 Working :

           When used as the protocol for the delivery of messages, the sending process continues to send a number of frames specified by a window size even after a frame loss. Unlike Go-Back-N ARQ, the receiving process will continue to accept and acknowledge frames sent after an initial error; this is the general case of the sliding window protocol with both transmit and receive window sizes greater than 1.

The receiver process keeps track of the sequence number of the earliest frame it has not received, and sends that number with every acknowledgement (ACK) it sends. If a frame from the sender does not reach the receiver, the sender continues to send subsequent frames until it has emptied its window. The receiver continues to fill its receiving window with the subsequent frames, replying each time with an ACK containing the sequence number of the earliest missing frame. Once the sender has sent all the frames in its window, it re-sends the frame number given by the ACKs, and then continues where it left off.

              The size of the sending and receiving windows must be equal, and half the maximum sequence number (assuming that sequence numbers are numbered from 0 to n−1) to avoid mis-communication in all cases of packets being dropped. To understand this, consider the case when all ACKs are destroyed. If the receiving window is larger than half the maximum sequence number, some, possibly even all, of the packages that are resent after timeouts are duplicates that are not recognized as such. The sender moves its window for every packet that is acknowledged

 Video explanation :

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OSI Model - How an email passes through each layer

The Open Systems Interconnection model (OSI model) is a product of the Open Systems Interconnection effort at the International Organization for Standardization.

 

It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar communication functions are grouped into logical layers. An instance of a layer provides services to its upper layer instances while receiving services from the layer below.

This video explains the process of how an email passes from one machine to another while traversing through the 7 layers of the OSI  model. Very Interesting video and clearly mentions about what happens to the email at each layer. Next time someone asks you "How OSI model plays an important role in our day to day life" , share this video or explain it yourself.


A complete self-explanatory video on the 7 layers of OSI model and its real-time application. It's an interactive video , so make sure that you click on continue buttons once understand the description at each step.

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Go Back N Protocol (With Animation) - Computer Networks

Go-Back-N ARQ is a specific instance of the Automatic Repeat-reQuest (ARQ) Protocol, in which the sending process continues to send a number of frames specified by a window size even without receiving an ACK packet from the receiver. Learn this from this perfect animation.

The receiver process keeps track of sequence number of the next frame it expects to receive, and sends that number with every ACK it sends. The receiver will ignore any frame that does not have the exact sequence number it expects -- whether that frame is a "past" duplicate of a frame it has already ACK'ed, or whether that frame is a "future" frame past the lost packet it is waiting for. Once the sender has sent all of the frames in its window, it will detect that all of the frames since the first lost frame are outstanding, and will go back to sequence number of the last ACK it received from the receiver process and fill its window starting with that frame and continue the process over again.

Three cases are covered: 
1. All Packets reach the receiver and send acknowledgements back to the sender.
2. Some Packets a lost on their way to destination. 
3. Some Acknowledgements are lost on their way back to sender.

                View the animation to understand The Protocol

(Click the Play Button to start)

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Data Communication [Comp - Sem 5 ] [IT - Sem 4]

Introduction

         The subject Data Communication introduced in 4th semester of IT Engineering and 5th semester of Computer Engineering is a very important subject in the curriculum of Engineering. This subject lays the foundation of Networking in Engineering. This subject needs to be understood thoroughly as you will be learning Computer Networks in the next semester. The Engineering syllabus includes in all, 3 subjects in networking : viz Data Communication, Computer Networks and Advanced Computer Networks (Elective). All these are very important for an engineer who wants to establish a career in Networking. 'Networking' is a very vast field for education and has immense scope and applications in the  industry. The demand for Network Engineers keeps on increasing day by day.

       Now , one point I would precisely state is, syllabus of Data Communication is a bit different for both Computer and IT. Its not totally different, but definitely there is  a considerable amount of difference. Beginning a word with the OSI model, I now assume that you are aware of the OSI model. If not please refer this link.

     In the OSI model you have been introduced that there are seven layers in the model : i.e.  Physical layer, data link layer ..... Presentation Layer. Now from these seven layers : the bottom most 2 layers viz : physical layer and data link layer will be introduced in the subject Data Communication.

   Now the rest 5 layers namely.,Network layer on wards will  be covered in the subject Computer Networks along with a few other important networking topics.

Analysis

Unit  1 :  Layer models and Signals

The first unit gives you introduction and a brief idea about the different terminologies and concepts which are pre-requisites for any networking concepts. This unit is extremely lengthy and a bit boring. The concepts introduced here do not allow you to enjoy unlike other networking topics. This unit is relatively easy to learn even very vast. Normally, most of the questions asked in this subject have appeared in the previous university papers.

Unit  2 : Modulation and Multiplexing

Relatively short unit , when compared to the first unit but a little bit confusing. A few concepts introduced here have already been introduced to you in the subject 'Basic Electronics Engineering' [FE - Sem 2 ]. These concepts again appear as they are. people who find Electronics tough will have to invest relatively little more efforts in this unit.

Unit 3 : Transmission media and Switching

Introduces the basic Networking topics to you. A very simple and easy to learn unit. Concepts are really interesting and can be easily understood with a simple glance. Diagrams are an important part of this unit. Scoring unit and very interesting.

Unit 4 : Error control and Data link Control

A lengthy  unit , relatively tedious and very a  bit boring. You will understand many concepts of networking in this unit ....which you will be required to understand in the other unit. Not difficult , but a few sums make learning this unit a bit complicated, relatively time consuming. This unit will  definitely need multiple glances to understand the concepts well.

Unit 5 : Multiple Access and Ethernet

Very easy unit. I enjoyed learning the concepts introduced in this unit. Many new concepts a glance will give you a brief idea about the concepts. Really interesting, most of the questions from this unit can be easily predicted. Scoring, simple and very easy unit.

Unit 6 :  Devices , Backbone networks and SONETS

Lengthy unit,mainly covers 3 main topics.Devices, Backbone networks and SONETS , which are completely different from each other. Neat diagrams allow you to score in this unit. Simple but not as simple as 5th unit.

Books to Refer

     Among the local author's I would suggest only Techmax. The book is written by the well known author and publisher J. S. Katre. The book covers all the concepts mentioned in the syllabus. The book is complete in itself. Students, sometimes tend to avoid techmax and prefer Technical , since the Techmax books are huge in  size when compared to no of pages. Please, do not prefer Technical for D.C as many concepts are incomplete.

Among the foreign authors, I would suggest , the best one : Data Communication and Networking -Behrouz Forouzan. This book will help you to learn the concepts with simple diagrams and a lucid language.  

Verdict

    Data Communications a.k.a  D.C is a very lengthy  and a bit difficult for the beginners. The subject is very interesting as well as  a very important subject in the curriculum. Scoring is not that difficult...neat diagrams and quality answers will easily fetch you 65+ marks in this subject. Scoring 70+ will need good efforts and very precise answers . Totally theoretical  but very easy to learn and not that difficult.

Books for Download

Data Communication & Networking
Behrouz Forouzan


(Most Recommended)

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Understanding Data Communications

Gilbert Held

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Data and Computer Communications 

William Stallings

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Computer Networks : PU Sem 5 [ I.T.] and Sem 6 [Comp]

This is one of the most interesting subject I have ever studied in my engineering career. Computer Networks is an easy,very interesting and scoring subject. When i say scoring ...i mean scoring above 70. This subject is purely conceptual. You really  need to understand the concepts to learn this subject.


  A kind advice: please use only a proper reference Book to learn this subject!!!.........
  I personally would recommend : Andrew S. Tannenbaum


  To enjoy this subject please use the book mentioned above only...........Techmax is also good ...but only exam point of view.!!....


  You can download the Torrent from the below link:

Computer Networks - A. Tanenbaum

 Download this torrent  : Computer Networks : Andrew S Tanenbaum

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Alternative Download

Computer Networks - A Systems Approach

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 Unit 1 : N/w Layer 1 - Very easy.... you will need to revise the concepts of data communication for this unit. All the topics can be easily understood using the PPT's provided by the official site of Andrew S. Tanenbaum.
                                  
 Unit 2: N/w Layer 2  - Very Interesting....I loved this unit. This unit is really important concerning your viva
 as most of the conceptual questions are asked from this unit.


              Download  PPT's  for learning NETWORK LAYER 


Unit 3:Transport Layer - Ok,this unit is not at all tough.again even this unit is important concerning your viva.


                 Download PPT;s for learning TRANSPORT LAYER


Unit 4:Application Layer - Another very interesting unit................I really  loved this unit also@!!. U can     understand this unit very well ..if u use the internet a bit for practical purposes!!!


                 Download PPT's for learning APPLICATION LAYER


 Unit 5: Multimedia - Here you understand the basic process of a video broadcasting and other similar 
 processes ......if you have a jist of idea about how youtube and your browser works..
 you will easily  catch this unit.


  Unit 6: Wirelesss: - Interesting..but still..you will  need to mug up certains topics...


                     DOWNLOAD ANDREW S. TANENBAUM PPT's

#Note - Please note that scoring 70+ in C.N. is not at all a difficult task. Even though a theory paper..you can write the complete paper using the concepts....

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