[T11.3] FCP-4: Continuously Increasing SEQ_CNT

Bob.Nixon at Emulex.Com Bob.Nixon at Emulex.Com
Fri Oct 13 16:08:51 PDT 2006

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Despite the potential value of CISC to FCP operation in Class 3, we must
advise against requiring or even recommending it.
In our interoperability testing, we have discovered there are devices with
significant installed base that do not behave properly when actually
presented with CISC.  Unfortunately, they do not reject an N_Port Login that
offers CISC, so this problem is not discoverable.
Even recommending CISC in a standard would therefore increase the incidence
of interoperability problems with use of Fibre Channel.
   - Bob Nixon, Emulex alternate representative
-----Original Message-----
From: t11_3-bounces at listserve.com [mailto:t11_3-bounces at listserve.com]On
Behalf Of David Peterson
Sent: Sunday, October 08, 2006 12:34 PM
To: t10 at t10.org
Cc: t11_3 at t11.org
Subject: [T11.3] FCP-4: Continuously Increasing SEQ_CNT
Howdy All,
At the last FCP-4 working group meeting I presented a proposal to request the
use of continuously increasing SEQ_CNT (CISC) for Class 3 service.
While most believe requiring continuously increasing SEQ_CNT for Class 3
service is a good idea, one vendor indicated that none of their
implementations support CISC, and another vendor was concerned about the
As such, we have the following options:
a. require CISC for Class 3 service. This means that existing implementations
can claim compliance to a prior standard (e.g., FCP-3);
b. specify that CISC should be used for Class 3 service;
c. no change (i.e., CISC is not required except for streamed Sequences).
My preference would be option a.
What say ye?
(no disclaimer)

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