Time-dependent. Pronounced eye-sock-ra-nuss, it refers to processes where data must be delivered within certain time constraints. For example, multimedia streams require an isochronous transport mechanism to ensure that data is delivered as fast as it is displayed and to ensure that the audio is synchronized with the video.
Isochronous can be contrasted with asynchronous, which refers to processes in which data streams can be broken by random intervals, and synchronous processes, in which data streams can be delivered only at specific intervals. Isochronous service is not as rigid as synchronous service, but not as lenient as asynchronous service.
Certain types of networks, such as ATM, are said to be isochronous because they can guarantee a specified throughput. Likewise, new bus architectures, such as IEEE 1394, support isochronous delivery.