6.4.1.1 List Priority
As stated previously, the lists built up by the Host Controller Driver are classified as either
periodic or nonperiodic. The Interrupt list and the Ischronous list are periodic because the
endpoints on those lists require service at specific times in a deterministic manner. The Control
list and the Bulk list are nonperiodic because endpoints on those lists can tolerate latency and
expect service only on a time-available basis.