data transfer type
...time. All devices support control transfers intended for configuration and management purposes. These transfers must be error-free, but don't need to have bounded service periods. Mass storage devices (eg. removable disk drives) support bulk transfers. These transfers must be error-free, but they don't need to have either a bounded service period or a guarantee of bus bandwidth. Bulk transfers may take a long time to complete. The following table shows the key attributes associated with each transfer type. TRANSFER TYPE I s o c h r o n o u s I n t e r r u p t C o n t r o l B u l k Periodic • • Time-relevent • Bounded Latency • Guaranteed Maximum Service Period • • Bandwidth Guarantee (by type) • • • Bandwidth Guarantee (by endpoint) • • Error-free (lossless) • • • USB ARCHITECTURE Wired bus (tiered star topology) Polled (token-based) bus Single host per bus Separate CRC pro...