This paper is a brief review of the USB 3.0 implementation, focusing on USB 2.0 backward compatibility and on the major features associated with the Super- Speed (SS) bus. The goal is to provide the reader with a short and concise description of USB 3.0, and enough detail to give a good feel for the technology, protocols, and techniques.

USB 3.0 retransmission mechanisms are different from USB 2.0 because of the new routing infrastructure. USB 3.0 has separate retransmission mechanisms in the Link and the Protocol Layers for optimizing data buffering in devices and hubs. This document examines the traffic exchanged between two link partners (such as a host and a device) when a DPH is received as invalid by one end.

USB 3.0 substantially increases the required support for Power Management at the system level. Compliant SuperSpeed Devices will use inactivity timers or device usage profiles to aggressively place SuperSpeed links into the low power states. To ensure USB 3.0 provides a favorable user experience with minimal device latency, entrance and exit from low power states must occur within rigid pre-defined time limits. The USB 3.0 specification currently defines a exit latency of ~10us for devices movi