The networks must be transparent to the users. The network and the distributed applications running on it must be as reliable as if they were running on a single computer. In addition, the network must provide self-healing capabilities that can reroute network traffic around broken cables and failed components and be flexible enough to react to business-related changes in its environment.
Local area networks used to be very simple but now they are different structures, at least five computation standards for transmissions, and two standards for the information required to manage the network. Local area networks have become so complex that they require their own operating system.
Networking continues to be the least understood and most critical component in an organization’s Information infra-structure. Most organizations committed to client/server computing agree that linking Local area networks is not the place to skip to save money. The advice is to try not link is compatible Local area networks with different platforms such as hardware, software and operating systems.
1. Interconnected device
2. Backbone networks
3. Desktop high-speed local area network
As Local area networks spread through an organization, bridges and routers are used to connect them. For example, a router could be used to move information among Ethernet, token ring and fiber distributed data interface networks. Users would most likely not realize the full 100MHz of fiber distributed data interface throughout; because the router is manage all connections.
Backbone networks also connect Local area networks, but also provide high-speed transmission and control the flow of data among the various networks. High speed Local area network connects desktop machines directly to the fiber distributed data interface network and, therefore, it has access to the full 100MHz transmission speed. This configuration is designed for high volume, data intensive applications, such as those that transmit graphics information and images.
The two most common Local area networks are Ethernet and International Business Machine’s token ring. Ethernet uses base band coaxial cable or shielded pair wire and can operate at 10MHz. Its protocol is carrier sense multiple-access with collision detection.
This requires a sending device to monitor the network and send the message only it senses the network is not in use. If a collision is detected, the device must stop the transmission and try again when it senses the network is clear.
Token ring uses shielded pair wire or optical cables and can operate at 4 or 16MHz. Its protocol is called token ring. A special signal code, called a token, is passed from stations to station. If a device wants to transmit a message, it wants for the token to come by, takes it of the network, and transmits its message. The token is return to the network after the transmission is completed.