Defining Bandwidth and Network Capacity

Bandwidth and network capacity are measures of the effective performance of the communication links that connect the server computer to the network. Effective performance refers to performance judged by actual, observed values, as opposed to theoretical values that might be achieved in an ideal environment. A server's effective performance is determined by the individual capacity of each network segment and by the ability of the server to respond to requests.

Bandwidth refers to the rate at which data is transmitted and received over a communication link between a computer and the network. Bandwidth is measured in several different ways:

The rate at which bytes are transferred to and from the server.

The rate at which data packages are sent by the server. Data packages include frames, packets, segments, and datagrams.

The rate at which files are sent and received by the server.

Effective bandwidth varies widely depending upon the transmission capacity of the link, the server configuration, and the server workload. The values for a single server also change as it operates, in response to demand and to competition for shared network resources.

Network capacity is a broader term that refers to the ability of the server and the communication link to carry network traffic and support multiple resources. Network capacity is measured, in part, by the number of connections established and maintained by the server.

The following sections describe in more detail the methods you can use to measure bandwidth and network capacity on your server.