Thursday 21 June 2012

TELNET

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PSTN INTERNET CONNECTIVITY ppt


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Introduction


Chapter 1. Introduction


Each of the past three centuries has been dominated by a single technology. The 18th century was the era of the great mechanical systems accompanying the Industrial Revolution. The 19th century was the age of the steam engine. During the 20th century, the key technology was information gathering, processing, and distribution. Among other developments, we saw the installation of worldwide telephone networks, the invention of radio and television, the birth and unprecedented growth of the computer industry, and the launching of communication satellites.
As a result of rapid technological progress, these areas are rapidly converging and the differences between collecting, transporting, storing, and processing information are quickly disappearing. Organizations with hundreds of offices spread over a wide geographical area routinely expect to be able to examine the current status of even their most remote outpost at the push of a button. As our ability to gather, process, and distribute information grows, the demand for ever more sophisticated information processing grows even faster.
Although the computer industry is still young compared to other industries (e.g., automobiles and air transportation), computers have made spectacular progress in a short time. During the first two decades of their existence, computer systems were highly centralized, usually within a single large room. Not infrequently, this room had glass walls, through which visitors could gawk at the great electronic wonder inside. A medium-sized company or university might have had one or two computers, while large institutions had at most a few dozen. The idea that within twenty years equally powerful computers smaller than postage stamps would be mass produced by the millions was pure science fiction.
The merging of computers and communications has had a profound influence on the way computer systems are organized. The concept of the ''computer center'' as a room with a large computer to which users bring their work for processing is now totally obsolete. The old model of a single computer serving all of the organization's computational needs has been replaced by one in which a large number of separate but interconnected computers do the job. These systems are called computer networks. The design and organization of these networks are the subjects of this book.
Throughout the book we will use the term ''computer network'' to mean a collection of autonomous computers interconnected by a single technology. Two computers are said to be interconnected if they are able to exchange information. The connection need not be via a copper wire; fiber optics, microwaves, infrared, and communication satellites can also be used. Networks come in many sizes, shapes and forms, as we will see later. Although it may sound strange to some people, neither the Internet nor the World Wide Web is a computer network. By the end of this book, it should be clear why. The quick answer is: the Internet is not a single network but a network of networks and the Web is a distributed system that runs on top of the Internet.
There is considerable confusion in the literature between a computer network and a distributed system. The key distinction is that in a distributed system, a collection of independent computers appears to its users as a single coherent system. Usually, it has a single model or paradigm that it presents to the users. Often a layer of software on top of the operating system, called middleware, is responsible for implementing this model. A well-known example of a distributed system is the World Wide Web, in which everything looks like a document (Web page).
In a computer network, this coherence, model, and software are absent. Users are exposed to the actual machines, without any attempt by the system to make the machines look and act in a coherent way. If the machines have different hardware and different operating systems, that is fully visible to the users. If a user wants to run a program on a remote machine, he [] has to log onto that machine and run it there.
[] ''He'' should be read as ''he or she'' throughout this book.
In effect, a distributed system is a software system built on top of a network. The software gives it a high degree of cohesiveness and transparency. Thus, the distinction between a network and a distributed system lies with the software (especially the operating system), rather than with the hardware.
Nevertheless, there is considerable overlap between the two subjects. For example, both distributed systems and computer networks need to move files around. The difference lies in who invokes the movement, the system or the user. Although this book primarily focuses on networks, many of the topics are also important in distributed systems. For more information about distributed systems, see (Tanenbaum and Van Steen, 2002).
The first linkage of computing and communication devices occured in 1940, when Dr. George Stibitz used telegraph lines to send data files from Dartmouth college in New Hampshire, USA to a Bell Laboratories calculator in New York city, USA.


1.0 UNDERSTAND bASICS OF dATA COMMUNICATION.
1.1 define data communications.
1.2 need for data communication networking.
1.3 distinguish between analog and digital transmission.
1.4 explain serial and parallel communication.
1.5 define baud rate, simple, half duplex and full duplex communication.
1.6 define channel capacity.
1.7 list different transmission media.
1.8 explain the cross section and applications of twisted pair cable, UTP, STP, co-axial cable, optical fibre.
1.9 know about infrared and light wave transmission.
1.10 explain about data and signals (digital data digital signals, digital data analog signals, analog data digital 1.11 signals, analog data analog signals).
1.12 compare characteristics of transmission media.
1.13 explain shannon capacity.

Tuesday 19 June 2012

Repeaters ppt


Ports & Sockets ppt


POINT TO POINT AND MULTI POINT PPTS


INTRANET ppt


Bridges and Gateways


dccn previous question papers for diploma


·         MARCH /APRIL-2008
·         MARCH /APRIL-2009
·         OCT/NOV-2011
·         APRIL/MAY-2012
·         OCT/NOV-2012



BOARD DIPLOMA EXAMINATION, (C-09)
MARCH /APRIL-2008
DECE.-VI SEMESTER EXAMINATION
DCCN

TIME: 3 Hours]                                                                     [Total Marks :100]
PART   - A
INSTRUCTION:  (1) ANSWER ALL QUESTION AND EACH QUESTION
                                           CARRIES 4 MARKS
                    (2)  ANSWER SHOULD BE BRIEF AND   STRAIGHT      TO  THE POINT AND SHALL NOT EXEED FIVE SIMPLE SENTENCES

1.     Distinguish between analog and digital transmission.
2.     Explain about infrared and light wave transmission.
3.     Explain the difference between circuit switching and packet switching.
4.     List the applications of WAP.
5.     Define ISP and PSTN.
6.     Define Intranet.
7.     List the different layers of TCP/IP
8.     Explain the need of FRAME relay.
9.     Explain DNS namespace.
10.  List HTTP commands.


Instructions :    (1) Answer any five questions and each question carries 12 marks.                  (2) The answers should be comprehensive and the criteria for valuation   is the content but not the length of the answer.

11.   Explain UTP, STP, Co-axial cable and fibre optical cable with cross-sectional view.
12.   Explain in detail with diagrams about STAR, BUS, RING, topologies.
13.   (a) describe CDMA communication. (b) explain FDDI and its properties.
14.   (a) describe ARPA NET and www. (b) explain ISDN architecture.
15.   (a) explain the packet transfer mechanism using routers and OP address. (b) describe ATM.
16.   (a) explain the IP addressing concepts and classes and default gatway service. (b) explain the use of UDP.
17.   (a) describe I detail web browser architecture. (b) discuss in detail about hyperlinks.
18.   (a) explain the purpose of proxy server. (b) explain the ftp in web application in detail.






Ring Topology



signals are continuous in nature.