RIng topology

Ring topology:

In this topology, each node is connected to two and only two neighboring nodes and forms, a close loop, • It is fast, short cabling and reliable but break in loop affects all devices on network, difficult to configure and troubleshoot.

b) Bus Topology:

b) Bus Topology:

It consists of a single length of transmission medium(normally coaxial cable) onto which various nodes are attached i.e. it provides a common or shared communication pathway, It is easy to install. extend, needs short cabling, low cost but difficult to troubleshoot and less reliable.

LAN Topology:

LAN Topology:-

The pattern of interconnection of nodes or workstations in a network is termed as a network topology, Before selecting a topology one should consider on the factors such as cost, flexibility and reliability of the topology. Some common LAN topologies are:

a) Star Topology:

It consists of a central hub to which all other nodes are connected by a single path. The advantage of the star topology is that every connection is dedicated to one user so it gets full bandwidth of the channel, easy to troubleshoot and simple access protocol. Its disadvantage is high cost of media and equipment needed to supply individual connection and central node dependency,

Types of Network

Types of Network:-

The computer networks vary in size, complexity and geographical spread. Mostly on the basis of a geographical spread, there are three basic types of networks, which are:
1. Local Area Network (LAN)
2. Metropolitan Area Network (MAN)
3. Wide Area Network (WAN)
Local Area Network (LAN): It is a small computer network that is confined to a localized area, such as a building, an office or a factory. LANs are found in most business enterprise, government offices, and educational institutions. The key purpose of a LAN is to serve its users in sharing data, information, programs, printer, hard disk, modem, etc. In this network, computers are mostly connected with a physical medium such as a twisted pair cable or coaxial cable.

Network Architecture

Network Architecture

Depending upon the involvement/contribution of computers in a network system, there are two types of network architecture which are, client/server architecture and peer to peer architecture,
Client/Server Architecture
A network architecture in which each computer or a process on the network is either a client or a server, Servers are powerful computers or processes dedicated to managing disk drives (file servers), printers (print servers), or network traffic (network servers). Clients are PCs or workstations on which users run applications. Clients rely on servers for resources, such as files, devices, and even processing power,
Peer-To-Peer Architecture
It is often referred to simply as peer-to-peer, or abbreviated P2P. It is a type of network in which each workstation has equivalent capabilities and responsibilities. Unlike the client/server architectures, in which some computers are dedicated to serving the others, in this architecture, each node (a computer in network) may have equal contribution to the system and available system resources can be shared among them.

Network Hardware

Network Hardware:

Network hardware directs the flow of data over the network channels.

Network Interface Card (NIC): It is a network adapter, a small circuit board designed to plug into an expansion slot on a computer motherboard, It accesses the physical media that link computers, receive packets from the network software, and transmits instructions and requests to other computers.

Network Hub: It is a device that joins communication lines together. There are two types of hubs viz, passive hub (which add nothing to the transmission) and an active hub (which may regenerate signals to boost strength as well as monitor activity).

Repeater: A device that amplifies or regenerates the data signals in order to extend the distance of a transmission.

Router: A device that examines the destination address of a message and selects the most effective route. It is used in complex networks where there are many pathways between users.

Bridge: A device that connects two networks of the same type together, a contrast with a gateway.

Gateway: A computer that inter-connects and performs the protocol conversion between two dissimilar types of networks, contrast with a bridge.

MODEM: A modulator and demodulator, a communication device that converts digital signals to A/F (audio frequency) tones, which are in the frequency range that the telephone lines can transmit and also convert the transmitted tones back to digital signals.ATM : Automated Teller Machine, a special purpose device with a keypad and display unit, connected to bank's computer in order to serve the remote financial transaction.

Communication Channel

Communication Channel

The media through which the communication is established or the workstations are interconnected is called communication channel. A network may use a physical medium such as cables and optical fibers or/and wireless medium such as radio wave or micro wave for communication. The transmission capacity of a communication channel is termed as Bandwidth,
The most commonly used communication channels are:

Twisted-pair cable: It is just like a telephone cable, which consists of copper wires twisted together and terminates in a square plastic RJ-11 or RJ-45 plug or connector.

Coaxial cable:It is like cable-TV or cable with a round, silver BNC connecter at either end and is a high-capacity communication cable consisting of a copper wire conductor, non- conducting insulator, metal shield (net), and plastic outer coating.

Fiber-optic cable: It consists of a bundle of extremely thin tube of glass. Each tube, called an optical fiber, is much thinner than a human hair. It usually consists of a strong inner support wire; multiple strands of optical fiber, each covered by a plastic insulator and a tough outer covering.