stds-1394: RE: SBP-2 Study Group

Peter Johansson PJohansson at
Fri Aug 11 00:16:47 PDT 2000

* From the T10 Reflector (t10 at, posted by:
* Peter Johansson <PJohansson at>
At 10:22 AM 8/10/00, Atsushi Nakamura wrote:

>If it is decided that work is done on a peer to peer SBP-2, I would like 
>to see the outcome
>1) not be "yet another protocol", and it remains "SBP-2" as we see it today
>2) does not sacrifice the effeciency and simpleness it has today as a 
>master-slave transport.
>Though it would be ideal if SBP-2 can handle both, it would not be worth 
>much if too much burden (inclucing compatibility) is put on the original 
>protocol, or significant changes are required for the new protocol which 
>results in something drastically different from what we have now.

It's hard to predict, in advance, how much interest there will be in an 
SBP-2 that is more peer-to-peer than the present. I think draft standard 
IEEE P1394.3 has done a pretty good job of enabling more symmetric 
connections between two SBP-2 devices, no matter which one is the initiator 
and which the target. With the benefit of hindsight it's easy to say that 
PPDT could have been a natural part of SBP-2---but now that it has been 
done as an add-on standard, would it be worthwhile to insert it into SBP-2?

If there are other ideas to explore about SBP-2 and peer-to-peer, that's 
one thing that study group time is for.

I understand your points, Ats, that there is a legacy base to consider 
whenever any modifications are made to an extant protocol. I don't think 
they should impede "brainstorming", else one might prematurely shut the 
door on new ideas. But once interesting new ideas have been created, they 
have to be subject to careful examination. And I think your concerns would 
be part of any thorough review.


Peter Johansson

Congruent Software, Inc.
98 Colorado Avenue
Berkeley, CA  94707

(510) 527-3926
(510) 527-3856 FAX

PJohansson at

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