wait for configuring

Tim Symons Tim_Symons at pmc-sierra.com
Mon Jan 30 10:32:30 PST 2006


* From the T10 Reflector (t10 at t10.org), posted by:
* Tim Symons <Tim_Symons at pmc-sierra.com>
*
The managmenent application client (whether an HBA or a self-configuring expander device) has information on the type of attached device from the IDENTIFY frame.

When a device type of greater than 001b responds  with the CONFIGURING bit set to one in the REPORT GENERAL response, then the application client shall wait until it receives a BROADCAST (CHANGE) on the port.
What it does in the time between is vendor specific. It is logical that other ports would be checked.

This condition occurs when an HBA is attached to a self-configuring device, or a self-configuring device is attached to another self-configuring device. Today's managmen application client already handles this case. Are timers used in todays HBAs for the case that a the configuring response is not received?

The result of a time-out should be a BROADCAST (CHANGE) issued by the Application Client device, because this will cause a re-initialisation of the attached device.

Regards
       Tim.

Tim Symons
Principal Engineer
PMC-Sierra Ltd.
Burnaby

Cell: 778 998 5025
E-mail Tim_Symons at pmc-sierra.com


-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org]On Behalf Of Ralph
Weber
Sent: Friday, January 27, 2006 5:24 PM
To: T10, Reflector
Subject: Broadcast (Change) overload


* From the T10 Reflector (t10 at t10.org), posted by:
* Ralph Weber <roweber at ieee.org>
*
Regarding Rob's comment:

  "The BROADCAST (CHANGE)s may thrash for a while, but
  will stop when the expanders are not detecting any more
  changes."

In keeping with the bull-in-a-china-shop style I have
exhibited so far, I cannot help but wonder if BROADCAST
(CHANGE) is overloaded. Currently, it seems to serve two
functions:

  - Telling other Expanders to reassess their self-config-
    uration status
  - Telling HBAs to kick off a serious sweep through the
    SAS Domain looking for configurable devices

The HBA action induced by the expander-based thrashing of
BROADCAST (CHANGE)s cannot be helpful in the overall config-
uration process. Until the thrashing settles down, every
entry of the HBAs into the picture throws more unproductive
traffic on the links.

Have I missed something?

.Ralph

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