Computer Network Parameters: Connectivity, Availability and Performance!
A computer network is judged on the basis of the following parameters:
ii. Availability or access and
Connectivity refers to the ability of each element in the system to exchange data with the other elements. The connectivity requirements are defined by the form of the DDP system. Some DDP systems may require links only to the locations above and below in a hierarchical structure or to the next horizontal structure.
Some others may warrant direct links among all the locations thus, requiring a very high degree of connectivity. Geographically dispersed locations also sometimes determine the degree of connectivity.
A high degree of connectivity improves the quality of information to users. But it has a cost; it costs money and adds to complexity of the network. Even more important is the problem of being able to develop and maintain acceptable levels of security standards to ensure safety and privacy of information in a highly connected network.
Therefore, there is a need to be selective in deciding about the degree of connectivity and undue leverage in this regard may have its adverse impact on the success of the network.
Availability in a network refers to the percentage of time that an element or user gets in the total time of the network. In case of high availability requirements, the network has to be organised in such a way that the failure of a single computer or device will not obstruct communication.
Use of parallel processors and alternate communication links are set to ensure high degree of availability. Improving availability would mean having higher investments in robust communication links and computer hardware. In case of time critical applications, it is essential to maintain high degrees of availability.
But, in the case of batch processing applications, it is possible to sacrifice availability to save on costs. For example, on-line trading system for securities must have high degree of availability whereas a financial accounting system need not have high degree of availability.
The performance of a network is assessed by the nature of the DDP and the applications it supports. In case of highly interactive DDP systems, quicker response from the processor is more important and thus response time becomes a critical measure of performance.
Whereas, in DDP systems that are used for moving large volumes of data, speed of transmission of data between the user and the host system becomes more critical.
It is, therefore, essential to clearly define and lay out the plan for the corporate network, in the light of needs of users and technologies for developing and maintaining networks. The network planning would involve identifying the users of network, grouping them according to the nature of their communication requirement, defining various types of data to be included in the traffic and selecting suitable network architecture for the enterprise.
It is important to realise that the users and their needs have increased overtime and the composition of traffic has also undergone complete metamorphosis. Today, computer networks are planned to handle different types of data traffic such as transactions data, bulk transfer of data files, conversational communication such as text mail, images of documents, voice, video, etc.
Advances in communication technology have also changed the way the networks are designed today; the change in economics of various communication links has changed the way the network planning is done today.