SMP REQUEST/SMP RESPONSE timer query

Penokie, George George.Penokie at lsi.com
Mon Oct 14 08:58:50 PDT 2013


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1310143_f.htm">HTML-formatted message</a>

Apoorva,
The answer to both of your questions is that: It is not specified by the
standard.
Bye for now,
George Penokie
LSI Corporation
3033 41 St NW
Rochester , MN 55901
507-328-9017
george.penokie at lsi.com
From: Apoorva Vats [mailto:apoorva.vats at synopsys.com]
Sent: Monday, October 07, 2013 7:52 AM
To: Penokie, George; t10 at t10.org
Subject: RE: SMP REQUEST/SMP RESPONSE timer query
Hi George,
Thanks for the reply.
But still, I am having some queries.
Please see my in lined responses marked as AV.
Firstly, I have few queries regarding 100 us timer :-
1)	What happens if Initiator doesn't transmit SMP REQUEST frame even
after 100 ìs get passed after the connection is established?
(GP - Nothing)
(AV -- No further question)
2)	Why this timer is running in SMP Initiator instead of SMP Target ? I
believe the SMP Target should wait for 100 us after SMP connection is
established to receive a SMP Request Frame.
(GP - The target is required to be able to accept frames immediately after
transmitting an open accept. The requirement on the Initiator port is correct
and if not met allows the target to shut down the connection. Of course, the
shutting down part  is not currently defined in the standard.)
(AV - You have replied in this query that "if not met allows the target to
shut down the connection". So my query is that how will the target decide
when to shut down  the connection )
Secondly, following queries are with respect to 1900 us time limit:
1)	What happens if Target doesn't transmit SMP RESPONSE frame even after
1900 ìs get passed after receiving SMP REQUEST frame.
(GP  - Nothing)
(AV -- No further question)
2)	Why this timer is running in SMP Target instead of SMP Initiator ? I
believe the SMP Initiator should wait for 1900 us after SMP request is sent
to receive a SMP Response Frame.
(GP -  The initiator is required to be able to accept frames immediately
after receiving an open accept.  The requirement on the target port is
correct and if not met allows the initiator to shut down the connection. Of
course, the shutting down part	is not currently defined in the standard.)
(AV - You have replied in this query that "if not met allows the initiator 
to shut down the connection". So my query is that how will the Initiator
decide when to shut down  the connection.)
I would like to write a proposal for this.
Please share some template to refer.
Regards,
Apoorva
From: Penokie, George [mailto:George.Penokie at lsi.com]
Sent: Tuesday, October 01, 2013 9:25 PM
To: Apoorva Vats; t10 at t10.org<mailto:t10 at t10.org>
Subject: RE: SMP REQUEST/SMP RESPONSE timer query
Apoorva,
You are correct in your assumption that the way the standard is written today
these time limits have no consequences if violated.  To make them more
relevant or less relevant a proposal will have to be written (not by me).
That proposal will have to be submitted  as an SPL-3 letter ballot comment.
To answer your questions:
Firstly, I have few queries regarding 100 us timer :-
1)	What happens if Initiator doesn't transmit SMP REQUEST frame even
after 100 ìs get passed after the connection is established?
(GP - Nothing)
2)	Why this timer is running in SMP Initiator instead of SMP Target ? I
believe the SMP Target should wait for 100 us after SMP connection is
established to receive a SMP Request Frame.
(GP - The target is required to be able to accept frames immediately after
transmitting an open accept. The requirement on the Initiator port is correct
and if not met allows the target to shut down the connection. Of course, the
shutting down part  is not currently defined in the standard.)
Secondly, following queries are with respect to 1900 us time limit:
3)	What happens if Target doesn't transmit SMP RESPONSE frame even after
1900 ìs get passed after receiving SMP REQUEST frame.
(GP  - Nothing)
4)	Why this timer is running in SMP Target instead of SMP Initiator ? I
believe the SMP Initiator should wait for 1900 us after SMP request is sent
to receive a SMP Response Frame.
(GP -  The initiator is required to be able to accept frames immediately
after receiving an open accept.  The requirement on the target port is
correct and if not met allows the initiator to shut down the connection. Of
course, the shutting down part	is not currently defined in the standard.)
Bye for now,
George Penokie
LSI Corporation
3033 41 St NW
Rochester , MN 55901
507-328-9017
george.penokie at lsi.com
From: owner-t10 at t10.org<mailto:owner-t10 at t10.org> [mailto:owner-t10 at t10.org]
On Behalf Of Apoorva Vats
Sent: Monday, September 23, 2013 1:46 AM
To: t10 at t10.org<mailto:t10 at t10.org>
Subject: RE: SMP REQUEST/SMP RESPONSE timer query
Hi ,
I sent a Query regarding SMP REQUEST/SMP RESPONSE timer on August 22 and
Did not receive any update on this.
Please update on this query.
Regards,
Apoorva
From: Apoorva Vats
Sent: Thursday, August 22, 2013 12:24 PM
To: t10 at t10.org<mailto:t10 at t10.org>
Subject: SMP REQUEST/SMP RESPONSE timer query
Hi,
As specified in  "SAS Protocol Layer - 3 (SPL-3) " version specification
(T10/BSR INCITS 492)( Revision 02 / 16 January 2013)
Page no. 443
6.20 SMP link layer
6.20.1 SMP frame transmission and reception
Inside an SMP connection, the SMP initiator phy transmits a single
SMP_REQUEST frame within 100 ìs and the SMP target phy responds with a single
SMP_RESPONSE frame (see 8.4) within 1 900 ìs.
And at page no. 547
						       Table 187 - MT_TP time
limits
Time limit
Value
Description
SMP Response time limit
1 900 ìs
Maximum time from receiving an SMP_REQUEST frame to transmitting an
SMP_RESPONSE frame
Here specification specifies 2 timers. 1 for Request frame and other for
Response frame.
1)	100 ìs timer runs at Initiator end and;
2)	1900 ìs timer runs at Target end.
And at page no.548
8.4.5.3.3 MT_TP2:Respond state
8.4.5.3.3.1 State description
This state waits for a Send SMP Response request, which includes the
following argument:
a) Response Bytes.
After receiving a Send SMP Response request, this state shall construct an
SMP_RESPONSE frame using the arguments from the Send SMP Response request and
send a Transmit Frame request to the port layer within the SMP Response time
limit specified in table 187 (see 8.4.5.3.1).
This specifies that within SMP Response time limit SMP RESPONSE frame should
be sent by the Target  but no action is specified in the specification, if
this does not happen within this time limit.
Similarly, Specification does not mention anything if  SMP initiator phy does
not transmit SMP_REQUEST frame within 100 ìs.
Firstly, I have few queries regarding 100 us timer :-
1)  What happens if Initiator doesn't transmit SMP REQUEST frame even after
100 ìs get passed after the connection is established?
2)  Why this timer is running in SMP Initiator instead of SMP Target ? I
believe the SMP Target should wait for 100 us after SMP connection is
established to receive a SMP Request Frame.
Secondly, following queries are with respect to 1900 us time limit:
3) What happens if Target doesn't transmit SMP RESPONSE frame even after 1900
ìs get passed after receiving SMP REQUEST frame.
4) Why this timer is running in SMP Target instead of SMP Initiator ? I
believe the SMP Initiator should wait for 1900 us after SMP request is sent
to receive a SMP Response Frame.
Regards,
Apoorva



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