The TCP/IP Guide  9  Networking Fundamentals       9  Network Performance Issues and Concepts

Balancing Network Performance with Key Non-Performance Characteristics 1 2 3 Understanding Performance Measurement Units

Throughput

Throughput is a measure of how much actual data can be sent per unit of time across a network, channel or interface. While throughput can be a theoretical term like bandwidth, it is more often used in a practical sense, for example, to measure the amount of data actually sent across a network in the “real world”. Throughput is limited by bandwidth, or by rated speed: if an Ethernet network is rated at 100 megabits per second, that's the absolute upper limit on throughput, even though you will normally get quite a bit less. So, you may see someone say that they are using 100 Mbps Ethernet but getting throughput of say, 71.9 Mbps on their network.

The terms bandwidth and throughput are often used interchangeably, even though they are really not exactly the same, as I just discussed.

This very important, often overlooked term, refers to the timing of data transfers on a communications channel or network. One important aspect of latency is how long it takes from the time a request for data is made until it starts to arrive. Another aspect is how much control a device has over the timing of the data that is sent, and whether the network can be arranged to allow for the consistent delivery of data over a period of time. Low latency is considered better than high latency.

Balancing Network Performance with Key Non-Performance Characteristics 1 2 3 Understanding Performance Measurement Units