I have uploaded another release candidate for PPR1 of the MS/TP
Large Frames proposal. I was asked at the last SSPC to look into
how to support other network layers (e.g. IPv6) through the current
BACnet MS/TP data link interface.
I honestly couldn't figure out how to do this without creating more
confusion. My conclusion was and is that the best way to describe
how to interface other network layer clients to MS/TP was to add a
MAC layer interface or remain silent on the topic.
Clause 9 already acknowledges that proprietary frames are not BACnet.
However, it says nothing about sending or receiving such frames. The
important point is that there *is* a MAC header that provides
addressing, frame length and type.
In discussing the "silent" approach with Dave Robin, he suggested
that ASHRAE could maintain a registry of reserved frame types just as
it does Vendor IDs. Reserved frame types for non-BACnet clients
(e.g. IPv6 Encapsulation) could be allocated from time to time without
the need to change Clause 9.
The technical content of the proposal remains unchanged. The major
differences since last time include:
- Removed the MA-UnitData abstract interface
- Removed all references to IPv6 Encapsulation frames
- Changed all occurrences of "proprietary types" to "types"
I look forward to discussing this proposal in the MSTP-WG. Please
let me know if you have any comments or questions beforehand.
--- In firstname.lastname@example.org, email@example.com wrote:
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> File : /Add-135-2010an-PPR1-draft-rc11.docx
> Uploaded by : kerlyn2001 <kerlyn2001@...>
> Description : Agnostice, but silent, on support for other network layers like IPv6.
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