Network Topology | Types of Network Topology | Network

Today, we are discuss about the Network, Topologies, Classification of Network. in today’s life network is the most important part so we should know about the Network.

What is Network ?

A computer network can be simply defined as the interconnection of two or more independent computers. Applications of computer networks are found everywhere. They are used in our homes, schools, colleges, railway stations, offices and business. They help us to send an email, watch a live sports event at our computer, book rail/air tickets and do chatting with our friends.

Advantages

• Resources sharing
• High reliability
• Cost-benefit advantage
• Scalability
• Powerful communication medium

Network Topology

Network topologies is the arrangement of mapping of the elements (links, node etc.) of a network interconnection between the nodes. It also determines the strategy for physically expanding the network, in future. Topologies can be physical or logical. Physical Topology means the physical design of a network including the devices, location and cable installation. Logical Topology refers to the fact that how data actually transfers in a network as opposed to its design.

There are different types of network topologies like bus, Ring, star etc.

Bus Topology

• Bus topology is a single common communication to which all the computer are connected.
• It has a single length of cable with a terminator at each.
• It is a passive topology, which means only one computer at a time an send a message.
• Bus topology is the simplest and most widely used local area network design.
• Each node is connected to others nodes.
• The network operating system keeps track of a unique address of each node and manages the flow of data between machines.
• This is accomplished by using data frames which contain source and destination addresses.

Advantages of Bus Topology

• It is simple, reliable, and easy to be used in a small sized local area network.
• It is easy to implement and extend using connectors.
• If one computer on the bus fails, it does not affect the rest of the traffic on the bus.
• Less expensive than other cabling arrangements.
• It requires least amount of cable to connect computer.

Disadvantages of bus topology

• In this topology, no two computers can transmit data at the same time.
• Terminators are required at both ends of the cable.
• It does not cope well with heavy load which can slow down a bus considerably.
• Performance degrades as additional computers are added.

Ring Topology

• Ring topology is also known as circular topology.
• This layout is similar to the linear bus.
• Each node is connected to two and only two neighboring nodes.
• It is made of short segments that connect one PC to the next PC
• A ring is an active network and is not subject to the signal loss problems.

Advantages of Ring Topology

• It performs better than a star topology under heavy network load.
• It can create much larger network using Token Ring.
• It does not require network server to manage the connectivity between the computers.

Disadvantage of Ring Topology

• It is difficult to troubleshoot.
• It is much slower than an Ethernet network under normal load.
• Ring topology are more expensive than Ethernet cards and hubs used in bus topology.

Star topology

• Each computer on a network communicates with a central hub.
• Central hub also called as a concentration.
• A hub expands one network connection into many.

Advantages of Star Topology

• Use of multiple cables types in a same network with a hub.
• It is more reliable if one computer fails whole network is not disturbed.
• It is easy to replace, install or remove hosts or other devices, problem can be easily detected.
• It has good performance

Disadvantages of Star Topology

• Requires more cable length than a linear topology.
• If the hub, switch, or concentration fails, nodes attached are disabled.
• More expensive than linear bus Topologies because of the cost of the hubs, etc.

Network Classification

There are mainly Three types of network

• LAN (Local Area Network)
• MAN (Metropolitan Area Network
• WAN (Wide Area Network)

LAN

• Less Costly.
• LAN is a group of computers located in the same room, same building, same floor are connected to form a single network as to share a resources such as disk drives, printer, data etc.
• LAN is a private network.
• LANs operate at relatively high speed when compared to the typical WAN (.2 to 100 MB /sec).
• LAN is generally limited to specific geographical area less than 2 Km., supporting high speed networks.
• The most widely used LAN system is the Ethernet system based on the bus topology.

Advantages

• It allows sharing of expensive resources such as Laser printers, software and mass storage devices among a number of computers.
• LAN allows for high-speed exchange of essential information.
• It contributes to increased productivity.

Disadvantages

• Some type of security system must be implemented if it is important to protect confidential data. The security may be further low if it is a wireless LAN.

MAN

• It is developed in 1980s.
• More Costly.
• Metropolitan area networks, or MANs, are large computer network that spans a metropolitan area or campus.
• Its geographic scope falls between a WAN and LAN.
• They typically use wireless infrastructure or Optical fiber connections to link their sites.
• A MAN is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities.
• MANs can also depend on communications channels of moderate-to-high data rates.
• MANs might also be owned and operated as public utilities or privately owned.
• Metropolitan area networks can span up to 50km, devices used are modem and wire/cable.

WAN

• Costliest.
• The largest and most well-known example of a WAN is the Internet.
• Wide Area Network is a network system connecting cities, countries or continents, a network that uses routers and public communications links.
• WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations.
• Communication medium used are satellite, public telephone networks which are connected by routers.