METHOD AND APPARATUS FOR SAS OPEN ADDRESS FRAME PROCESSING IN SAS EXPANDERS

摘要

SAS expanders are commonly used within a SAS network topology to allow multiple disk drives (targets) to connect to multiple host devices (initiators). A connection between an initiator and a target is setup inside an expander on the pathway between the initiator and the target. A source device sends a connection request message called an open address frame using in-band signaling. The expander processes the open address frame and forwards an modified open address frame to the next expander in the path or to the final destination device.

主权项

1. A method for protocol error handling in a connection request between a source PHY and a destination PHY in a serial attached SCSI (SAS) network, the method comprising:
receiving, at the source PHY, a stream of bytes of an SAS open open address frame; before completion of receiving all of the bytes of the SAS open address frame:
a) at the source PHY, performing an open address frame cut-through by forwarding an open request from the source PHY to an expander connection manager (ECM) of a SAS expander;b) loading an open request context from the source PHY to the ECM, the open request context being a subset of the SAS open address frame;c) at the ECM, performing an open request context cut-through by performing an address lookup to determine the destination PHY while loading the open request context from the source PHY; andd) at the source PHY, detecting a protocol error in the received bytes of the SAS open address frame, the protocol error comprising a SAS primitive within the SAS open address frame, and at the ECM, aborting the address lookup and the loading of the open request context, before completion of either the address lookup or the loading of the open request context.