Port9100 clarifications

Port9100 clarifications

Port9100 clarifications

JK Martin jkm at underscore.com
Fri Sep 6 11:12:00 EDT 1996


> The discussion on this point was that Randy had already added the
> correct information in the August 1996 updated Printer MIB. This
> wording was accepted as stated.
> For those of you who have not looked at the latest MIB, here is the
> wording that was approved:
>                    chPort9100(11),   -- Bi-directional printing protocol
>                                      -- utilizing TCP port 9101 for control
>                                      -- and TCP port 9100 for data.
>                    chAppSocket(12),  -- Adobe Systems, Inc.

Sorry, but I remain confused.  I posted the following to the PWG list
on August 24th:

> I believe these descriptions are not quite accurate.
> The "chPort9100" type is (and always has been, IMHO) a simple description
> of what HP had started with its network-capable LaserJet (ie, JetDirect)
> products.  This method involves a *single* stream (TCP) connection to the
> device to transfer a print job, with modest "back channel" return of job
> information.  It is *not* similar to LPD in any way, shape or form, nor
> does it use a second stream connection.
> Ironically, the "chAppSocket" channel type, on the other hand, has always
> been described as being *exactly* as shown in your description for the
> "chPort9100" type above.
> I distinctly recall when Steve Zilles (Adobe) originally submitted the
> chAppSocket channel type, since this type of technology is of critical
> interest to my company (Underscore).

Bill Wagner later responded on Sept 3rd with:

>      As Jay pointed out, the e-mail requested changes between port 9100 and 
>      AppSocket do not reflect what was originally submitted by Adobe or HP. 
>      The changes and the origin of these changes should be identified.

Going back thru the archives, the earliest posting I could find that
talks about AppSocket is from Steve Zilles, dated 2 March 1994, in
which he wrote:

> Some examples of "channels" in use today are:
>      serial port channel           bi-directional data channel
> [...]
>      Adobe AppSocket(9101) channel a bi-directional extn of LPD
>      port 9100 channel             HP and friends

In that same message Steve later wrote:

>      Adobe AppSocket = 12  -- Bi-directional protocol used by Adobe
>                            -- Transcript software to submit and
>                            -- monitor print jobs
>                            -- Adobe Systems, Inc.

Tom Hastings later wrote (on 12 May 1994):

> I'll also change:
>      chanPAP(7)          -- Apple
>      chanRPrinter(9)     -- Novell
>      chanPserver(10      -- Novell
>      chanAppSocket(12)   -- Adobe 9101

Steve Zilles then responded (on 27 June 1994):

> 14. The comment associated with the AppSocket type for Channels needs to
> specify the 9101 is used for control and 9100 is used for data. That is,
>                      appSocket(12),       -- a bi-directional, LPD-like
>                                           -- protocol using 9101 for 
>                                           -- control and 9100 for data
>                                           -- Adobe Systems, Inc.

I'm not sure if the down-casing of "AppSocket" to "appSocket" was a
typo or not.  Anyone from Adobe care to comment?

Steve later wrote (on 6 July 1994) this when posting a major summary
of "closed" issues:

> 99)  The comment on the AppSocket type in the Channels Table needs
>      clarification
>      CLOSED: revised text was accepted.

Since the last known posting on the AppSocket definition was from
Steve (as shown above), shouldn't this represent the official

Similarly, can anyone from HP comment on whether the definition for
chPort9100 (as shown at the top of this message) is indeed correct?
Specifically, does that protocol actually employ a pair of ports for
separate control and data channels?  (My working knowledge is that
chPort9100 only uses a single channel, and that control is embedded
within the data stream sent over port 9100.)

I just want to make sure these definitions are indeed correct in the
final, Draft version of the MIB.


More information about the Pwg mailing list