SAS, AIP (Normal)

Elliott, Robert (Server Storage) elliott at
Fri Mar 5 08:09:56 PST 2004

* From the T10 Reflector (t10 at, posted by:
* "Elliott, Robert (Server Storage)" <elliott at>

> -----Original Message-----
> From: owner-t10 at [mailto:owner-t10 at] On Behalf 
> Of Gil Romo
> Sent: Thursday, March 04, 2004 5:27 PM
> To: t10 at
> Subject: SAS, AIP (Normal)
> * From the T10 Reflector (t10 at, posted by:
> * Gil Romo <gil.romo at>
> *
> Hello,
> There is a rule in, "Expanders shall transmit an AIP 
> ... within 128 dwords of receiving an OPEN address frame".
> I believe this rule is obsolete, since expanders now wait for 
> a confirmation from the ECM before transmitting AIP.
> Expanders must transmit an AIP such that it is received 
> before the Open Timeout Timer times out.
> ------------
> Gilbert Romo
> Circuits & Integration
> QLogic Corporation, Aliso Viejo, California
> Office: 949-389-6266
> E-mail: gil.romo at

No, the rule hasn't changed.  Any ECM needs to be able to acknowledge
within that time.  

Even before the Arbitrating (Normal) change, it was understood that 
requiring the expander to transmit within 128 dwords was overkill 
for meeting the 1 ms timer.  So is the "shall transmit every 128 
dwords" rule after the first one.  They serve as a reminder that 
the expander is working on the request and isn't hung.  We didn't 
want to worry about any race conditions between 1 ms timers
on both sides, either.

Rob Elliott, elliott at
Hewlett-Packard Industry Standard Server Storage Advanced Technology

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