Standardizing Alternate Encodings

By chance, this same conversation bubbled up over on the oBIX list today. Participants in one of the Smart Grid standards committees who are particularly interested in this issue might want to sign on to oBIX as well, at least as an observer. Note: I am not saying Brian’s proposal is the answer. I am saying that the small device side of the conversation is being engaged in such a way that interoperability with the larger economic conversations can be reasonably handled.

"A man should never be ashamed to own that he has been in the wrong, which is but saying ... that he is wiser today than yesterday." -- Jonathan Swift

Toby Considine

Chair, OASIS oBIX TC
Facilities Technology Office
University of North Carolina
Chapel Hill, NC

Email: Toby.Considine@ unc.edu
Phone: (919)962-9073

http://www.oasis-open.org

blog: www.NewDaedalus.com

From: Frank, Brian [mailto:bfrank@tridium.com]
Sent: Tuesday, March 31, 2009 11:26 AM
To: obix-xml@lists.oasis-open.org
Cc: brian.tridium@gmail.com
Subject: [obix-xml] Proposal for Alternate oBIX Encodings

Today oBIX defines an abstract object model with a single encoding based on XML. But the original vision behind oBIX was that multiple encodings could be defined all sharing the same interoperable object model. I would like to propose adding two alternate encodings of the oBIX object model to the 1.1 draft specification: JSON and Binary.

One of the things we are starting to see is many people are using oBIX as an AJAX data feed to their browser. In this use case, it is preferable to deliver the oBIX information directly in a JSON format rather than requiring JavaScript to parse the XML into a usable format.

Why a binary oBIX encoding? This requirement takes a little more background discussion. One of the technologies I have been deeply involved in is 6LoWPAN which is an RFC specifying how to run IPv6 over 802.15.4 wireless networks. I firmly believe that 6LoWPAN has the potential to unleash the Pervasive Internet by adding billions of new nodes to the Internet. But putting these devices onto the Internet is just the first step. The next step is to put them onto the Web so that they can be wired into humanities existing information infrastructure. Due to their resource and power constraints, 6LoWPAN devices cannot fully run HTTP or mange XML payloads. To the solve the HTTP problem, I am working on an RFC to run a compressed version of HTTP over 6LoWPAN. On the payload side, oBIX fits perfectly for defining a RESTful information model. But we need a compact encoding which can work with the small packet sizes required for 802.15.4 networks. I have some good ideas on how to achieve this without loosing any of oBIX’s modeling capability.

Clients would perform negotiation with servers for their preferred encoding using the Accept header (standard HTTP content negotiation).

Comments?

I would suggest we try to setup a teleconference next week (Mon or Tue preferably) to discuss this strategy.

Brian

smartgrid-interest message