IPP Mail Archive: Re: IPP> NOT - device-to-host events, not end-user events

Re: IPP> NOT - device-to-host events, not end-user events

Tom Hastings (hastings@cp10.es.xerox.com)
Wed, 11 Mar 1998 17:20:44 PST

At 11:10 03/11/1998 PST, Ron Bergman wrote:
>Tom,
>
>I certainly agree with Jay on this subject. I don't know of any transport
>that does not provide some method of flow control. Certainly TCP provides
>an excellent flow control mechanism.
>
>I don't recall this requirement discussed in any of the meetings in
>Austin. Where did this come from?

Paul Moore suggested this. It is NOT flow control but rather
advisory to a host that is controlling a large number of devices
at once. Paul says he has NT systems that control a large number of
devices, like 500, so that knowing which devices the host is getting
ahead and which devices the host is falling behind in getting PDL data
to the device would be useful. My understanding of what Paul was saying
was that the host would then increase the priority of the threads that
were getting behind and lower the priority of the threads that were
getting ahead.

Or does TCP/IP have such advisory events (as opposed to stop sending
and start sending)?

Tom

>
>
> Ron Bergman
> Dataproducts Corp.
>
>
>On Wed, 11 Mar 1998, Jay Martin wrote:
>
>> Tom Hastings wrote:
>> >
>> > In discussing the host-to-device requirements, we came up with a
requirement
>> > that the printer be able to feed back information about whether it was
>> > choked up with data or needed more data for the current job.
>> >
>> > So we could have events like:
>> >
>> > Slow down data transfer
>> > Speed up data transfer
>>
>> This doesn't quite sound right. I mean, flow control should be mandated
>> by the underlying transport, right? We certainly don't want to reinvent
>> such a key aspect of end-to-end communications within IPP.
>>
>> ...jay
>>
>> ----------------------------------------------------------------------
>> -- JK Martin | Email: jkm@underscore.com --
>> -- Underscore, Inc. | Voice: (603) 889-7000 --
>> -- 41C Sagamore Park Road | Fax: (603) 889-2699 --
>> -- Hudson, NH 03051-4915 | Web: http://www.underscore.com --
>> ----------------------------------------------------------------------
>>
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