questions about wide port

Elliott, Robert (Server Storage) Elliott at
Tue Jul 23 05:54:25 PDT 2002

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

> -----Original Message-----
> From: shogo hamasaku [mailto:hamasaku at] 
> Sent: Tuesday, July 23, 2002 3:23 AM
> To: t10 at
> Subject: questions about wide port
> Hello,
> I have some questions about wide port connection. I appreciate if 
> someone gives me the answer.
> I attached the file shows a connection for my question.
> Q1. Is this connection allowed?

> If yes, I have some additional questions.
> For example, the write command progresses as followings, and my 
> questions are in 4..
> 1. Initiator device opens the target device.
>      The link via Physical Link A-1 through Physical Link B will be 
>      established.
> 2. Target device issues XFER_RDY.
>      It goes through Physical Link B to Physical Link A-1.
> 3. Initiator device sends data.
>      It goes through Physical Link A-1 to Physical Link B.
> 4. Initiator device opens the same target device.
>  Q2. Is it allowed to send OPEN through A-2 while the connection 
>      via Physical Link A-1 through Physical Link B is already 
>      established?

Yes.  The initiator is allowed to try opening another connection
over A-2 if A-2 is free.  The connection may be to the same or to a
different target.

The initiator probably should not try this unless it knows it is
talking to a wide target, because it will just consume resources
and not provide any performance improvements (see below).

>  Q3. If allowed, (1) Does the expander device transfer the Open to 
>      Physical Link B after waiting for the close of current 
> connection?

Yes.  If the request were from some other initiator, the expander
would do the same.

> or (2) Does the expander device send OPEN REJECT? 

No, we don't have a reason code for "pathway is already open
for you, please use that one."

> or (3) Does the expander device recognize the link is currently 
> connected and send OPEN ACCEPT?

No, definitely not.

> -----------------------------------------------------------
> Shogo Hamasaku          hamasaku at

Rob Elliott, elliott at
Industry Standard Server Storage Advanced Technology

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