P1394> RE: [PP1394:00137]

P1394> RE: [PP1394:00137]

Atsushi Nakamura atsnaka at mxa.mesh.ne.jp
Fri Jan 9 10:47:31 EST 1998


Just for clarification;


I think we have 2 choices in defining a 
"PWG profile CDB ",


1st choice:
If we decide to define the PWG profile CDB in a way that there is 
a 1284.4 specific CDB content encapsulated in a
"generic CDB frame structure" (generic, meaning supporting various upper
layers) which is intended to support other upper layers as well as 1284.4,
we will need to define 2 things:


 1)"generic CDB frame structure"...will include header to distingush 
              actual content (ex. 1284.4, or other alternative layers)


 2)1284.4 specific CDB content  ....actual content of CDB which is 1284.4
information


2nd choice:
If we decide that the PWG profile CDB will be 1284.4 specific,
in this case we will only need to define:


1) 1284.4 specific CDB content


In either case,
1284.4 supportive flag and packet header will be included in 
1284.4 specific CDB content.
I AGREE that this 1284.4 "short-cut" may be effective 
AS LONG AS it is not defined in the "generic structure" but defined in
1284.4 
specific content definition.
    

---
Now, my opinion on making he PWG profile CDB "generic" vs making it 
"1284.4 specific".
Since SBP-2 already has a mechanism to distinguish the contents of the CDB
("command_set_spec_id" and "sw_version"), I think we do not need a "CDB
frame"
to do the same thing.
SBP-2 itself is already "generic"
I think the PWG profile should define the CDB to be 1284.4 specific.


P.S. Alan,Nagasaka-san, I apologize if this discussion is already out of
synch.
      I have not yet had time to read the updated profile.   


Atsushi Nakamura
Canon Inc.




----------
> $B:9=P?M(J : Nagasaka Fumio <Nagasaka.Fumio at exc.epson.co.jp>
> $B08 at h(J : 'ALAN_BERKEMA at hp-roseville-om2.om.hp.com'
> CC : 'p1394 at pwg.org'
> $B7oL>(J : P1394> RE: [PP1394:00137] 
> $BAw?.F|;~(J : 1998$BG/(J1$B7n(J9$BF|(J 16:59
> 
> Thank you Alan, for your great effort updating PWG profile document.
> 
> Larry wrote: (in "P1394> December Meeting Minutes")
> > H- Section 14, Multiple Logical Channels
> > Routing information needs to be provided here, not .4 Channel 
> information.
> $B%j(J	=> PSID and SSID should be removed from the command_block
> 
> At LA meeting, we agreed to remove PSID and SSID from CDB of normal
> command block ORB. However, now I would like to suggest to enclose
> 1284.4 supportive flag and 6 bytes 1284.4 packet header in CDB.
> 
> The reason is outlined below.
> 1)	IEEE 1284.4 is providing "out-of-band packet control flag" in the 
> header
> for 1284.4 packets.
> 2)	However if we does not enclose any 1284.4 information in normal 
> command
> block ORB. Fetch Agent needs to examine buffered data that wad 
> fetched
> after the fetch agent processed the ORB.
> 3)	Basically, out-of-band packet shall be extracted as soon as 
> possible.
> 4)	Thus we would like to make short cut to detect out-of-band requests 
> without
> reading buffer space associated with each ORB.
> 
> --------------------------------------------
> -------------------------------
> Fumio Nagasaka
> Epson Software Development Laboratory Inc.
> Tel +81 268 25 4111,  Fax +81 268 25 4627
> E-mail to nagasaka.fumio at exc.epson.co.jp
> 
> -----Original Message-----
> From:	ALAN_BERKEMA at hp-roseville-om2.om.hp.com 
> [SMTP:ALAN_BERKEMA at hp-roseville-om2.om.hp.com]
> Sent:	Friday, January 09, 1998 7:38 AM
> To:	pp1394 ML
> Subject:	[PP1394:00137]
> 
>  << File: ccMail >>  << File: pwgprof.pdf >>
> 




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