Notes on the History of the VWRAP Working Group

After my last post about VWRAP, a couple people pinged me asking about it's history. Here is a quick narrative of how VWRAP came to be and where it might be headed next.

The effort to establish the VWRAP working group has been ongoing for about a year, and it has a surprisingly rich history for an effort that's been ongoing for that short of a period of time. [This post was originally dated April 7th, 2010, -ed] Our group is certainly not the first attempt to develop inter-operable virtual worlds standards; that's been going on for quite a while.

VWRAP recent history begins with an interoperability test sponsored by IBM and Linden Lab in the summer of 2008. Using ideas that had been discussed in the Second Life™ architecture working group, several users were able to teleport their avatars from Linden-owned to systems owned by third parties.

There were significant limitations however. Avatar appearance was inconsistent across regions and cross-grid access to inventory was more or less nonexistent. But as a first step, it showed that cross-grid teleportation were possible.

Interested users can find documentation of the Open Grid Protocol (OGP) used by these early interop trials on the Second Life™ wiki:

  1. Introduction [1]
  2. LLSD [2]
  3. Authentication [3]
  4. Teleport [4]

Later that year we entered a time of economic uncertainty. Virtual world interoperability did not seem to contribute to the bottom line, and there were significant near-term opportunity costs. The consensus was we should type up a report on our experiences, publish our final OGP drafts and focus on less risky things for a few months before coming back to it. We were in the process of mothballing the interop effort when things took an interesting turn.

Inside the lab, we knew the UDP-based legacy Second Life protocol had some serious scalability problems; we wanted to move more services to LLSD over HTTP. Most of our work serialized LLSD messages as XML documents and sent them over the internet. As part of our "wrapping up" process, we figured we should register the MIME types we used for LLSD. this was the motivation for the original "LLSD Abstract Type System" [5] draft published in early 2009.

At around this same time, the Bidirectional HTTP (Bi-Di) effort inside the IETF was heating up and Mark Lentczner was asked to submit a draft and a presentation on "Reverse HTTP" [6] which was based on previous work at the lab with Donovan Preston.

Originally intended to be small, stand-alone drafts with a limited scope, we began the task of publishing an informational RFC for the purpose of registering the LLSD MIME types.

Starting a virtual worlds working group in the IETF was not a new idea. The SWMP mailing list had been setup in 2007 to discuss the idea. It eventually failed to result in a working group for reasons that are too complicated to discuss here. There was considerable resistance to the idea, but around this time, David Lavine at IBM started asking "what's next with interop?" David and Suzy Deffeyes had invested a fair amount of effort in the 2008 interop trail, so it was a reasonable question.

The more we talked about it, the more it seemed like a good idea. In early 2009, Mark Lentczner and I lobbied inside the lab for the idea while David and Suzy pushed the idea inside IBM. The IETF does not officially recognize corporate members, people who show up at IETF meetings represent themselves. But if a working group was ever to be formed, none of us felt comfortable pushing the idea without the support of our management.

We eventually produced an argument for interop good enough to garner support inside IBM and Linden, so in January of 2009, David Lavine of IBM and i approached the IETF informally with a proposal to sponsor the work of developing a virtual worlds interoperability prototype. At the time, we had hoped to develop a protocol that would work for a broad range of virtual experiences.

IETF process calls for a "Birds of a Feather" or BoF meeting to be held to see if there is sufficient interest to justify creation of an official working group. On march 24th, 2009 the "MMOX BoF" was held at the 74th IETF meeting in San Francisco, CA.

It did not go as well as we had hoped, but it didn't go as bad as we feared it could.

We were unable to reach consensus for "broad interoperability." we would not be able to, as David Lavine once hoped, "meet with your raiding party in the sims online, teleport over to world of warcraft, slay a dragon and then teleport to a pub in Second Life to celebrate."

But we did find there were enough people at Linden Lab and in the OpenSimulator community that were interested in cross-world interoperability. The IETF allowed us to redefine our scope and hold a second BoF session. On july 28th, 2009, the "OGPX BoF" was held to discuss the scope of the work (OGPX standing for "Open Grid Protocol X".) This meeting went well and following some discussion on the mailing list, we were able to agree to a group charter.

In the IETF, a working group charter defines what the group is supposed to be working on and what documents it proposes to produce. you can view the current charter for the group at the IETF's site [7]. Along the way, a number of people objected to the name "OGP" or "Open Grid Protocol" as they felt it implied the objective of the protocol was to manage cloud or grid based systems. Many alternate names were proposed including my favorites Open Virtual EnviRonments (OVER) and Agent BackbOne for Virtual Environments (ABOVE).

Eventually, we settled on the name "VWRAP: Virtual Worlds Region Agent Protocol."

As an aside, after changing the name from OGPX to VWRAP, we forgot to change the name of the mailing list until very recently. the current mailing list is, though there has been significant discussion on and

On march 23rd, 2010, the working group held it's first official face to face meeting in Anaheim, California. it was a mixed reality event with approximately 15-20 people being present in incarnate reality and 50 avatars attending in the virtual world.

The work continues on the vwrap mailing list, and anyone with an interest in virtual worlds interoperability is encouraged to participate.


  1. OGP Base Draft 3
  2. OGP LLSD Draft 3
  3. OGP Authentication Draft 3
  4. OGP Teleport Draft 5
  5. Linden Lab Structured Data
  6. Reverse HTTP
  7. VWRAP Working Group Charter