UniPro protocol stack: Difference between revisions

Revision as of 06:13, 7 October 2009

Revision as of 06:17, 7 October 2009

Line 88:

==PHY Adapter Layer (L1.5)==

The main user-level feature provided by L1.5 is to allow the bandwidth of a UniPro link to be increased by using 2, 3 or 4 lanes wherewhen neededa insteadsingle oflane justdoes onenot provide enough bandwidth. To the user, such a multi-lane link simply looks like a 2x,faster 3xphysical layer because the sybols are sent across 2, 3 or 4x4 fasterlanes physicalin layerparallel. Applications that mainly require very high bandwidth in one direction but require modestless bandwidth in the opposite direction, can have multiple lanes in onethe high bandwidth direction and a single lane in the other direction.

Architecturally, the PHY Adapter layer also serves to hide the differences between the alternative PHY technologies (D- and M-PHY). This abstraction thus mainly gives architectural flexibility. Abstracted PHY details include the various power states and employed symbol encoding schemes.