What is Computer Network?

Computer Network

Computer network means an interconnected collection of computers (or multiple processors software & hardware) such that they can:
Exchange information, Sharing resources each other
Examples:
Internet
Cellular Network

Key Issues For Computer Network

The following are the major key issues Computer Network:

Nature of Nodes: Whether participating nodes are homogeneous or heterogeneous in nature?

Topology: Which of the computer topology has to be followed? Computer topology accounts for the physical arrangement of participating computers in the network.

Interconnection Type: Whether interconnection type is point-to-point, multi-point, or broadcast type.

Reliability: 

How reliable our network is? Reliability aspect includes error rate, redundancy and recovery procedures.

Channel Capacity Allocation:Whether allocation of channel capacity is time-division or frequency division?

Routing Techniques: Whether message between nodes are to be routed through: Deterministic, Stochastic, and Distributed routing techniques?
Models: Which of the models i.e. analytical models, Queuing models, Simulation models, Measurement and Validation models are applicable?
Channel Capacity: What are the channel capacities of the communication lines connecting nodes?
Access: Whether computer access in the network is direct-access or through a sub-network?
Protocols: What levels, standards and formats are to be followed while establishing communication between participating nodes?
Performance: How is higher performance of computer network achieved? Response time, time to connect, resource utilization, etc. contribute towards performance of computer network.
Control: Whether centralized control, distributed control or hierarchical control of participating nodes of computer network is suitable?


Tag : Computer Network, 

What is Computer Networking ?

Networking is the concept of sharing resources and services. A network of computers is a group of interconnected systems sharing resources and interacting using a shared communications link (see Figure). A network, therefore, is a set of interconnected systems with something to share. The shared resource can be data, a printer, a fax modem, or a service such as a database or an email system. The individual systems must be connected through a pathway (called the transmission medium) that is used to transmit the resource or service between the computers. All systems on the pathway must follow a set of common communication rules for data to arrive at its intended destination and for the sending and receiving systems to understand each other. The rules governing computer communication are called protocols.
In summary, all networks must have the following:
A resource to share (resource)
A pathway to transfer data (transmission medium)
A set of rules governing how to communicate (protocols)

Fig: In its simplest form, a computer network is a two or more computer sharing
information across a common transmission medium.
Having a transmission pathway does not always guarantee communication. When two entities communicate, they do not merely exchange information; rather, they must understand the information they receive from each other. The goal of computer networking, therefore, is not simply to exchange data but to understand and use data received from other entities on the network.
An analogy is people speaking (See Figure), just because two people can speak, it does not mean they automatically can understand each other. These two people might speak different languages or interpret words differently. One person might use sign language, while the other uses spoken language. As in human communication, even though you have two entities that "speak," there is no guarantee they will be able to understand each other. Just because two computers are sharing resources, it does not necessarily mean they can communicate.
Because computers can be used in different ways and can be located at different distances from each other, enabling computers to communicate often can be a daunting task that draws on a wide variety of technologies.

Figure: Human communication is like a network

The two main reasons for using computer networking are to provide services and to reduce equipment costs. Networks enable computers to share their resources by offering services to other computers and users on a network. The following are specific reasons for networking PCs:

• Sharing files
• Sharing printers and other devices
• Enabling centralized administration and security of the resources within the system
• Supporting network applications such as electronic mail and database services