P1394 Mail Archive: Re: [PP1394:00177] RE: P1394> Print Protocols

P1394 Mail Archive: Re: [PP1394:00177] RE: P1394> Print Protocols

Re: [PP1394:00177] RE: P1394> Print Protocols

Atsushi_Nakamura (atsnaka@bsd.canon.co.jp)
Wed, 18 Feb 1998 09:42:03 +0900

1 clarifiaction, and 1 comment.

Stephen wrote ;

> 4) DPP is not a transport layer. The Thin Protocol (defined in the DPP

> spec) that sits BELOW DPP is a transport layer. I like Thin Protocol.

> It's very lightweight. I don't think anybody could complain about

> adding the code to implement Thin Protocol. It doesn't provide multiple

> channels, but it does do segmentation/reassembly. It provides a very

> generic and simple "stream" transport.

DPP(Direct Print Protocol) =

Thin Protocol (transport) + DPP Command Set(application cmd set)

(DPP is the name for both the transport and command set.)

Everything else you mentioned is correct.

Brian wrote;

>>4) DPP over 1394.


>>Sounds good. I have not seen enough of the detailed mechanism to determine

>>if it delivers (I need to learn more about DPP). Did receive some comments

>>at the TA about totally inventing a new mechanism instead of reusing

>>existing protocols, though it could be the right answer.

>I agree with the concerns of the TA. Any protocols we specify MUST provide

>solutions in a significantly better way than do the other available

>protocols. If they do not, companies will not implement our protocols, and

>they will end up being a waste of time. In addition, too many protocols

>can confuse the industry and our customers, diluting the effect of the

>primary ones.

I ,one of the proposing side of DPP also agree with everyone's concern.

However, we are not adding 10 more protocols, just ONE more.

AV/C+FCP(current) :most suited for isochronous data

SBP-2 :most suited for asynchronous pull

Thin would cover what would be missing :

thin transport :most suited for symmetrical asynchronous "push"


"most suited", of course is MY observation, there may be other opinions,

but I assume Thin, with IP1394 would cover (almost) everthing.


Of course I assume everyone would agree that the DPP application command set

is required for direct-printing, but that is out of the scope of this discussion.


<bigger>Atsushi Nakamura


BJ Technology Develpoment 22,

Canon Inc.

53 Imai Kami-cho

Nakahara-Ku, Kawasaki-shi

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