FW: Ladder Diagrams for Error Recovery update, T10/00-137r4

Zeitler, Carl Carl.Zeitler at COMPAQ.com
Wed May 31 12:50:03 PDT 2000

* From the T10 Reflector (t10 at t10.org), posted by:
* "Zeitler, Carl" <Carl.Zeitler at compaq.com>
The Ladder Diagrams for Error Recovery in FCP-2 are now available on the T10
Web site.  The intent is that these diagrams replace, where necessary, the
Ladder Diagrams in Annex D.  The Class 3 Diagrams show recovery for both in-
and out-of-order.  The difference being that certain time-outs are 0 for in
-order as there is no need to wait for out-of-order frames to die out.  But
the Error Recovery is the same per Annex D.  Class 2 out-of-order was
changed to overcome the problem of not being able to start the Sequence
Count at 0 for Sequence retransmission.  The simple solution was to retire
the Recovery Qualifier before entering Error Recovery as is done in Class 2
in-order. Thus there is a single set of diagrams that cover both in- and

So the only difference  between in-order and out-of-order is the value of
REC_TOV.  It is currently defined as 2 seconds for in-order and R_A_TOV/2 or
5 seconds for out-of-order.

There were concerns expressed at the May meeting that out-of-order was
exposed and risky and that it should be put in FCP-3 or in a separate Annex.
I would urge those who harbor those feelings to scrutinize these diagrams to
be able to express more succinctly their objections
to having them in a single Annex.  

See below for a pointer to the document, courtesy of John Lohmeyer.

Regards, Carl

Carl Zeitler
Compaq Computer Corporation
MS 150801, 20555 SH249, Houston, TX 77070
Phone:281-518-5258 Fax: 281-514-5270
E-Mail: Carl.Zeitler at compaq.com

-----Original Message-----
From: John Lohmeyer [mailto:lohmeyer at t10.org] 
Sent: Wednesday, May 31, 2000 1:17 PM
To: Zeitler, Carl
Cc: 'Snively, Bob'
Subject: Re: Ladder Diagrams for Error Recovery update, T10/00-137r4


I've posted your file at:



At 09:37 AM 5/31/2000, Zeitler, Carl wrote:
>John, could you please upload this to the T10 web site.  Thank you
>  <<FCP-2_LBComments2-T10-00-137r4a.ppt>>
>Regards, Carl
>Carl Zeitler
>Compaq Computer Corporation
>MS 150801, 20555 SH249, Houston, TX 77070
>Phone:281-518-5258 Fax: 281-514-5270
>E-Mail: Carl.Zeitler at compaq.com

John Lohmeyer                  Email: lohmeyer at t10.org
LSI Logic Corp.                Voice: +1-719-533-7560
4420 ArrowsWest Dr.              Fax: +1-719-533-7183
Colo Spgs, CO 80907
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