DIFFERENCE BETWEEN SWITCH ROUTER AND HUB.

               Hello friends after successful post on basic topologies osWorld is now going to post on inter connected devices.in networking interconnected devices are commonly used.there are four types of interconnected devices hub,switch,router and bridge.we know that we can connect two pc via lan cable easily. but if we want o connect more then one pc then we must have to use different topologies which is discussed in previous article.but there must be require interconnected device like hub or switch.so we get back to the point and let us talk about four basic interconnected device.

1:-HUB

                 hub is simply broadcast the message they do not know about the receiver.suppose there are 10 pc connected to hub.from the left hand side no 1 pc wants to send the message to the pc number 9 which is right side of the hub.then hub receive the message from pc number 1 and broadcast the message in all over network.this message is received by the pc who really wants that message.in this case receiver has to check that message is for it or not. 

 

2:-SWITCH

                switch is same as hub in structure.but the difference between switch and hub is that switch do not broadcast the message in the network.suppose in previous example we use switch instead of hub then switch receives the message from pc number 1 and sends that message to the pc number of 10 instead of broadcasting the message.

 

3:-ROUTER

               Routers are very common today in every network area, this is mainly because every network these days connect to some other network, whether it's the Internet or some other remote site. Routers get their name from what they do.... which is route data from one network to another.

For example, if you had a company which had an office in Sydney and another one in Melbourne, then to connect the two you would use a leased line to which you would connect a router at each end. Any traffic which needs to travel from one site to another will be routed via the routers, while all the other unnecessary traffic is filtered (blocked), thus saving you valuable bandwidth and money.

There are two types of routers: 1) Hardware routers 2) Software routers. 

4:-BRIDGE

                 bridge is same as switch but only one difference is there between switches and bridges is that bridge can reform the signal.this functionality is not provided by switch.

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BASIC TOPOLOGIES USED IN NETWORKING

              Hello friends after successful post on android osworld is now going to post about networking.network means connection of 2 or more devices using switch,hub,or router.switch,hub and rourter are called interconnected devices.today i will talk about 4 basic topologies which are used in networking.folloing are the basic four topologies.

      1:-mesh topology
      2:-star topology
      3:-ring topology
      4:-bus topology

1:-mesh topology

                              in this topology every device is connected to remaining all devices in the network.we can say every devices in the network are directly connected to each other.main advantage of mesh topology is if any connected link is fail then also whole network is in active state.

2:-star topology

                         





        in star topology every devices are connected to hub.they can communicate via hub.in star topology there are multipoint connection between devices and point to point connection between device and hub.easy to reconfigure and isolation.

3:-ring topology

                           in ring topology every devices connected via repeater.there are point to point connection between every devices.in ring topology we can communicate in unidirecation only.if any device is fail we can say whole network is death.repeater is used for regenerate the origenal signal.

 

4:-bus topology

                           in bus topology there is one backbone line and n drop lines every device is connected to backbon using tapes via drop lines.in bus topology there is multipoint connection between all devices.becauseof that multi point connection not easy to isolation in bus topology.

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RELATED ARTICALS:-
1:-INTRODUCTION TO COMPUTER NETWORKING
2:-ADVANTAGES OF COMPUTER NETWORKING
3:-DISADVANTAGES OF COMPUTER NETWORKING

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diadvantages of computer networking

• Expensive to Install

Although a network will generally save money over time, the initial costs of installation can be prohibitive. Cables, network cards, and software are expensive, and the installation may require the services of a technician.

 

• Data Security

If a network is implemented properly, it is possible to greatly improve the security of important data. In contrast, a poorly secured network puts critical data at risk, exposing it to the potential problems associated with hackers, unauthorized access.

 

• Cables May Break

One broken cable can stop the entire network.

 

• File Server May Fail

Although a file server is no more susceptible to failure than any other computer, when the files server "goes down," the entire network may come to a halt. When this happens, the entire hospital may lose access to necessary programs and files.

 

• Virus Infections

If any computer system in a network gets affected by computer virus , there is a possible threat of other systems getting affected too. Viruses get spread on a network easily because of the interconnectivity of workstations. Such spread can be dangerous if the computers have important database which can get corrupted by the virus.

 

To overcome Network Disadvantages

• Security issues and Virus Infections issues

The increase in businesses connecting their systems and using the Internet has its drawbacks. When all computers are networked, one user's problems may affect everyone. You should consider the greater potential for data loss, security breaches and viruses when creating a network.

It is important to ensure data security through regular backing up the files, password routines, and system logs. It is important to remove access from employees who leave, otherwise they may still be able to access customer records.

As your data will be stored in one location on the server, physical security is very important. You should improve the quality of your system security to protect your business from potential virus attacks and hacking. This should include anti virus software and a firewall or software barrier.

If your staffs need to access the network while off-site, consider a virtual private network. This creates a secure link and protects information sent and received.

• File Server Fail down issues

For this we can have backup fail server. When the files server "goes down," then we can use the backup fail server. Having backup server we can overcome this problem.

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Benefits of the computer Networking

        In most organizations, a network offers benefits, such as data sharing and online communication that are not provided by a stand-alone environment (An environment in which there is several computers that are not connected to each other is called a stand-alone environment.). In this topic, you will identify the benefits of a network.

• Data sharing

The data can be easily sharable in a network so other user can access it at any time. For example, a user working in a team wants to share some data with the other team members. In a stand-alone environment, to share the data you can verbally exchanging information or writing memos or putting the data on a floppy and copying it to the machines of other members. If it network the data can be easily made sharable in a network so that the other team members can access.

A centralized data storage system enables multiple users to access data in different locations.

• Resource sharing

Resource sharing is also an important benefit of a computer network. For example, if there are four people in a family, each having their own computer, they will require four modems (for the Internet connection) and four printers, if they want to use the resources at the same time. A computer network, on the other hand, provides a cheaper alternative by the provision of resource sharing.

In this way, all the four computers can be interconnected, using a network, and just one modem and printer can efficiently provide the services to all four members. The facility of shared folders can also be availed by family members.

• Centralized Software Management

One of the greatest benefits of installing a network is the fact that all of the software can be loaded on one computer (the file server). This eliminates that need to spend time and energy installing updates and tracking files on independent computers throughout the building.

• Communication medium

A computer network can provide a powerful communication medium among people spread widely at different physical locations. It acts as a powerful communication medium when it comes to sharing information and resources.

• Data Security and Management

In a business environment, a network allows the administrators to much better manage the company's critical data. Instead of having this data spread over dozens or even hundreds of small computers in a haphazard fashion as their users create it, data can be centralized on shared servers. This makes it easy for everyone to find the data, makes it possible for the administrators to ensure that the data is regularly backed up, and also allows for the implementation of security measures to control who can read or change various pieces of critical information.

• Speed

Sharing and transferring files within Networks are very fast. Networks provide a very rapid method for sharing and transferring files. The sharing of data with the other users in a stand-alone environment requires physical transfer of data. This can be done by copying the data on a floppy disk or taking a printout. This requires more time and is inconvenient as compared to sharing the data over a network.

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Introduction to computer networking

Introduction

A network is a group of computers and other devices, such as printers and modems, connected to each other. This enables the computers to effectively share data and resources.

The concept of sharing resources over a network is called networking. The computers in a network can share data, messages, graphics, printers, fax machines, modems, and other hardware and software resources.

Network elements

• Servers

Servers are the computers that provide the shared resources to network users. There is usually only one server in a small network, but bigger networks may have more than one server.

 

• Clients

Clients are the computers that can access the shared network resources provided by a server.

• Media

The computers in a network are connected to each other by hardware components, such as cables. These components are called the media.

 

• Shared data

A server provides shared resources and data over a network. The files that are provided by the server over the network are called shared data. This shared data can be a document, a worksheet or a folder.

 

• Resources

Files, printers or other items that can be used by network users are known as resources. These resources can be either hardware or software resources.

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