SAS: Arbitration Fairness Clarification

Ed.W.Fong at Ed.W.Fong at
Mon Jun 17 09:47:02 PDT 2002

* From the T10 Reflector (t10 at, posted by:
* Ed.W.Fong at
In section 7.11.3 Arbitration fairness, for two connection requests
crossing on the physical link, a piece of text indicates that the winner is
determined by comparing field values in the Open address frames.

"If two connection requests pass on a physical link, the winner shall be
determined by comparing field values in this order: ..."

After the winner is determined internally by both devices, do both devices
still need to generate and wait for OPEN_ACCEPT and OPEN_REJECT to qualify
the winner?

The assumption is yes for generating but not for waiting based on the
transition from SL1:ArbSel to SL2:Selected.  Section Transition
SL1:SL2(ArbSel:Selected) indicates transition to SL2 after the arbitration
fairness rules are applied.  Section State SL2:Selected state
indicates that an OPEN_ACCEPT or OPEN_REJECT is generated.  But this state
does not indicate that it needs to wait for the reception of OPEN_REJECT or
OPEN_REJECT after generating the primitives for an open address frame that
is has received?  Does anyone else have a different interpretation?


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