Data Communication & Computer Network

The two types of network architectures are used: Computer Network Architecture Peer-To-Peer network Client/Server network Peer-To-Peer network Peer-To-Peer network is a network in which all the computers are linked together with equal privilege and responsibilities for processing the data. Peer-To-Peer network is useful for small environments, usually up to 10 computers. Peer-To-Peer network has no dedicated server. Special permissions are assigned to each computer for sharing the resources, but this can lead to a problem if the computer with the resource is down. Advantages Of Peer-To-Peer Network: It is less costly as it does not contain any dedicated server. If one computer stops working but, other computers will not stop working. It is easy to set up and maintain as each computer manages itself. Disadvantages Of Peer-To-Peer Network: In the case of Peer-To-Peer network, it does not contain the centralized system . Therefore, it cannot back up the data as the data is different in di

  The   Network   allows computers to   connect and communicate   with different computers via any medium. LAN, MAN and WAN are the three major types of the network designed to operate over the area they cover. There are some similarities and dissimilarities between them. One of the major differences is the geographical area they cover, i.e.   LAN   covers the smallest area;   MAN   covers an area larger than LAN and   WAN   comprises the largest of all. There are other types of Computer Networks also, like : PAN (Personal Area Network) SAN (Storage Area Network) EPN (Enterprise Private Network) VPN (Virtual Private Network) Local Area Network (LAN) – LAN or Local Area Network connects network devices in such a way that personal computer and workstations can share data, tools and programs. The group of computers and devices are connected together by a switch, or stack of switches, using a private addressing scheme as defined by the TCP/IP protocol. Private addresses are unique in relat

Transmission Modes in Computer Networks (Simplex, Half-Duplex and Full-Duplex) Transmission mode means transferring of data between two devices. It is also known as communication mode. Buses and networks are designed to allow communication to occur between individual devices that are interconnected. There are three types of transmission mode:-  These are explained as following below. 1. Simplex Mode   – In Simplex mode, the communication is unidirectional, as on a one-way street. Only one of the two devices on a link can transmit, the other can only receive. The simplex mode can use the entire capacity of the channel to send data in one direction.  Example: Keyboard and traditional monitors. The keyboard can only introduce input, the monitor can only give the output.  2. Half-Duplex Mode   – In half-duplex mode, each station can both transmit and receive, but not at the same time. When one device is sending, the other can only receive, and vice versa. The half-duplex mode is used in ca

  Analog and Digital Transmission There are a number of differences between analog and digital transmission, and it is important to understand how conversions between analog and digital occur. Let's look first at the older form of transmission, analog. Analog Transmission An analog wave form (or signal) is characterized by being continuously variable along amplitude and frequency. In the case of telephony, for instance, when you speak into a handset, there are changes in the air pressure around your mouth. Those changes in air pressure fall onto the handset, where they are amplified and then converted into current, or voltage fluctuations. Those fluctuations in current are an analog of the actual voice pattern—hence the use of the term  analog  to describe these signals (see  Figure 2.9 ). Figure 2.9  Analog transmission When it comes to an analog circuit—what we also refer to as a voice-grade line—we need to also define the frequency band in which it operates. The human voice,

PROTOCOL A Protocol is defined as a set of rules that governs data communications. A protocol defines what is to be communicated , how it is to be communicated and when it is to be communicated. For successful communication to occur, the sender and receiver must agree upon certain rules called protocol. ELEMENTS OF PROTOCOL A. Syntax It means the structure or format of the data. It is the arrangement of data in a particular order. B. Semantics It tells the meaning of each section of bits and indicates the interpretation of each section. It also tells what action/decision is to be taken based on the interpretation C. Timing It tells the sender about the readiness of the receiver to receive the data. It tells the sender at what rate the data should be sent to the receiver to avoid overwhelming the receiver. STANDARDS :  Standards are the set of rules  for data communication that are needed for  exchange of information among devices. It is important to follow Standards which are created b

Process of Data Communication: Data Communication   is defined as exchange of data between two devices via some form of transmission media such as a cable, wire or it can be air or vacuum also. For occurrence of data communication, communicating devices must be a part of communication system made up of a combination of hardware or software devices and programs. Data Communication System Components : There are mainly five components of a data communication system: Message   : Message is the information to be communicated by the sender to the receiver. Sender   : The sender is any device that is capable of sending the data (message). Receiver   : The receiver is a device that the sender wants to communicate the data (message). Transmission Medium   : It is the path by which the message travels from sender to receiver. It can   be wired or wireless and many subtypes in both  Protocol  :It is an agreed upon set or rules used by the sender and receiver to communicate data  A protocol is a s

  What is a Computer Network? A computer network is a set of devices connected through links. A node can be computer, printer, or any other device capable of sending or receiving the data. The links connecting the nodes are known as communication channels.  Computer Network uses distributed processing in which task is divided among several computers. Instead, a single computer handles an entire task, each separate computer handles a subset. What is Data? Data can be defined as a representation of facts, concepts, or instructions in a formalized manner, which should be suitable for communication, interpretation, or processing by human or electronic machine. Data is represented with the help of characters such as alphabets (A-Z, a-z), digits (0-9) or special characters (+,-,/,*,<,>,= etc.) What is Communication? Computer  communications  describes a process in which two or more computers or devices transfer data, instructions, and information. Network Basic Understanding A system o