Finally, Bob Herriot's work has been published. Relevant to
XHTML-Print, PWG PSIv1, FSG PAPIv1, UPnPv2, and others.
Please note the "IESG Note" at the beginning (see below).
- Ira McDonald
High North Inc
The IESG believes use of this media type is only appropriate in
situations where the producer is fully aware of the capabilities and
limitations of the consumer. In particular, this mechanism is very
dependent on the producer knowing when the consumer will need a
particular component of a multipart object. But consumers
potentially work in many different ways and different consumers may
need different things at different times. This mechanism provides no
means for a producer to determine the needs of a particular consumer
and how they are to be accommodated.
Alternative mechanisms, such as a protocol based on BEEP which is
capable of bidirectional communication between the producer and
consumer, should be considered when the capabilities of the consumer
are not known by the producer.
The Application/Vnd.pwg-multiplexed content-type, like the
Multipart/Related content-type, provides a mechanism for representing
objects that consist of multiple components. An
Application/Vnd.pwg-multiplexed entity contains a sequence of chunks.
Each chunk contains a MIME message or a part of a MIME message. Each
MIME message represents a component of the compound object, just as a
body part of a Multipart/Related entity represents a component. With
a Multipart/Related entity, a body part and its reference in some
other body part may be separated by many octets. With an
Application/Vnd.pwg-multiplexed entity, a message and its reference
in some other message can be made quite close by chunking the message
containing the reference. For example, if a long message contains
references to images and the producer does not know of the need for
each image until it generates the reference, then
Application/Vnd.pwg-multiplexed allows the consumer to process the
reference to the image and the image before it consumes the entire
long message. This ability is important in printing and scanning
applications. This document defines the Application/Vnd.pwg-
multiplexed content-type. It also provides examples of its use.