LAN (Local Area Network)
It is a data transfer system intended to link computers and associated devices within a limited geographical area. The key characteristic of a LAN’ is the fact that the whole of the network is confined to one site which is completely under the control of one organization.
Why LAN is required?
One of the original reasons for the user going in for ‘LAN’ was resource sharing both in terms of hardware and software resources
Today however more critical reason has emerged for user going in for LAN:
Diskless nodes of a network provide security by not allowing user to download data on floppy disk or upload unwanted viruses.
2. Expanded PC usage through inexpensive workstation
- Once a LAN has been set up it actually cost less to automate addition employees though diskless P.C.
- Existing PC can be easily connected into nodes by adding Network Interface Cards (NIC)
3. Organizational Benefits
- Data can be access from any nodes as data is stored centrally on the server.
- As data is centralized it becomes much easier to take backup and provides high level of security procedures.
4. It also reduces software cost:
- There is no need is buy multiple copies of the same software for every machine.
- Therefore, a software upgrades are much easier as any given package is stored centrally on the server.
5. It also provides the facility of e-mail and message broadcasting.
Advantage V/s Disadvantage
- It improves the data access as the organization can use fiber optic connections.
- Unlimited expansion is also possible with hub. Nodes can be added or removed with minimal disturbance to the network.
- Improved Administration: Centralized saving of data results in the cost-saving environment as it provides the feature of easy backup of the data
- It is quite expensive if it involves the use of fiber optic cables.
- It involves a heavy traffic network
Components of LAN( Local Area Network)
- It is principal computer with large disk storage on a network.
- It stores files and provides network nodes with access to these files.
When a program running on a node needs data from the server, it verifies the validity of the request and when every thing is satisfied it provides the accessibility of data.
2. Netwerk Operating System
- It is loaded in the server hard disk.
- It provides heterogeneous environment both in terms of hardware and software resources.
- In terms of hardware it should be flexible enough which means that it should be able to support large variety of hardware.
- In terms of software level it indicates that server operating system should be strong enough to deal with any type of operating system residing in the nodes
3. Network Interface Card (NIC)
- It provides the connection between the server & the workstation.
- An NIC has an additional memory for buffer incoming and outgoing data packets.
- It is a basic physical component of a networking which may comprise of hardware such as display unit, storage system etc.
- It is responsible to perform data entry operation such as addition, modification and deletion of the records.
- It is further classified in 3 different categories:
1. Intelligent Node 2. Dumb Node 3. Smart Node
5. Network Cabling
- In order to connect the computer system with server, network cabling is required.
There are 3 types of cables
o Twisted Pair Cables
o Coaxial Cable
o Fiber Optic Cable
Requirements of LAN(Local Area Network)
- It means ‘LAN operating system should be able to provide heterogeneous environment both in terms of hardware and software resources
- In terms of software level three should not be any fixation to any specific type of operating system.
- In terms of hardware, it should be flexible enough which means that it should be able to support large variety of hardware
2. Bridging of different “LAN
- User should be able to access any hardware or software resources in a very transparent
- User is not required to specify an extra command in order to access the system of other sites.
3. Growth Path & Modularity
- Modularity is one of the most important requirements of LAN
- A set of PC can easily be converted with latest technology.
- One should be able to attach another hard disk device.
- The server should be strong enough to manage the requirements of the new needs of the network
4. System Reliability & Maintenance
- All the computers are prone to power failure.
- If the server goes down the network becomes paralyzed, so in order to avoid these circumstances, there should be an alternative facility available.