Legacy compatibility for the SAS-2 SMP_RESPONSE frame time limit?

Day, Brian Brian.Day at lsi.com
Mon Apr 7 12:42:01 PDT 2008


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A SAS-2 SMP initiator does not have anything defined to enforce that
response time from an SMP target.... it is supposed to be tolerant of
arbitrary SMP response time still, for the very reason of backward
compatibility.
Likewise, there isn't a definition in SAS-2 SMP target to enforce the
100us time limit for SMP initiator to send the SMP REQUEST frame in the
connection.
However, it just "works out" to having bounded SMP performance when you
have SAS-2 compliant SMP devices on both sides of the connection.
Brian Day
LSI Corporation
________________________________
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Fore,
Chris
Sent: Monday, April 07, 2008 12:34 PM
To: t10 at t10.org
Subject: Legacy compatibility for the SAS-2 SMP_RESPONSE frame time
limit? 
SAS-2 added a time limit for SMP request completion of 1900us (see
sas2r14 7.18.1).
Would anyone care to comment regarding expected behavior when a SAS-2
SMP initiator is connected to a SAS-1.1 compliant SMP target that does
not adhere to this time limit? 
R. Chris Fore
Senior Engineer
RAID Engineering
NetApp
919.476.5155 Direct
Chris.Fore at netapp.com
www.netapp.com



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