the VWRAP protocol suite is being developed by a working group in the IETF. documents from this working group are the authoritative reference for the protocol. standards developed within an IETF working group begin as "internet drafts." there are frequently several revisions of an internet draft before it reflects the consensus view of the working group. when the working group believes an internet draft is ready, it is promoted to an RFC or "Request For Comments." if an RFC defines a normative standard, it may be placed on the "standards track." after a specification has been implemented and there is significant operational experience with the protocol it specifies, it may become an "internet standard." ( for the curious, this process is outlined in IETF RFC 2026.)
IETF specifications typically limit themselves to documenting protocol details. the " VWRAP : Introduction and Goals" document provides an overview of the VWRAP protocol suite, but does not provide software design information or a non-technical context for the VWRAP effort. supplementary documents are provided below to provide this information.
IETF documents
the VWRAP working group is at the beginning of the standardization process. as of april 2010, it has published a working group charter and several internet drafts. none of these drafts have been approved as RFCs.
- the VWRAP Working Group Charter
- this document briefly introduces the VWRAP working group. it describes the scope of the problem the group is seeking to solve, lists administrative contacts for the working group and lists the documents the group intends to produce.
- VWRAP : Introduction and Goals
- this document provides a detailed introduction to the working group's efforts. it describes the characteristics of VWRAP virtual worlds and sets objectives for the virtual world experience and requirements for the protocol. specific verbiage relating to the proposed architecture of VWRAP virtual worlds and deployment patterns are provided. it also includes a "document roadmap," describing the contents of other working group documents.
- readers new to VWRAP may want to consider reading the blog post, "what's the Virtual World Agent Region Protocol?" for a concise description. in 2009, co-author David Levine, working group co-chair Josh Bell and "mailing list regular" Morgaine Dinova co-authored the paper "VWRAP for Virtual Worlds Interoperability" [PDF] which also concisely describes the group's objectives and a bit of the history of the effort.
- before the working group was formed, one revision of this document was published under the title, "Open Grid Protocol: Introduction and Requirements." a slightly modified version of this draft was published after the formation of the working group with the title "VWRAP : Introduction and Goals." this will be the title of future revisions and the forthcoming RFC.
- in mid-2010 members of the VWRAP working group generally agreed that the draft reflected the group's consensus view and was adopted as an "official" draft. it's name changed from "draft-hamrick-vwrap-intro" to "draft-ietf-vwrap-intro" to reflect it's "official" status.
- VWRAP : Abstract Type System for the Transmission of Dynamic Structured Data
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the VWRAP protocols are intended to sit at the "application layer." this means that VWRAP protocol messages may be carried over HTTP, XMPP, RTP or raw UDP. other specifications in the VWRAP series use an interface description language and an abstract type system to specify protocol messages in a language and operating system neutral manner. the abstract type system and interface description language are defined in this document. guidelines for carrying VWRAP over HTTP and mime types for three serialization formats are provided as well.
- readers unfamiliar with the concept of an abstract type system may want to read the short blog post "VWRAP essentials : an abstract type system? hunh?" for a brief overview.
- LLSD and LLIDL, both defined by Linden Research and proposed as the abstract type system standard, were defined in a previous internet draft titled "Linden Lab Structured Data."
- in mid-2010 members of the VWRAP working group generally agreed that the draft reflected the group's consensus view and was adopted as an "official" draft. it's name changed from "draft-hamrick-vwrap-type-system" to "draft-ietf-vwrap-type-system" to reflect it's "official" status.
- VWRAP : Foundational Concepts and Transport Expectations
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this document provides a brief introduction and definition of foundational concepts referenced in VWRAP including capabilities and an HTTP based event queue. the current working group draft is radically similar to a previous draft that was published before the working group was created.
- in mid-2010 members of the VWRAP working group generally agreed that the draft reflected the group's consensus view and was adopted as an "official" draft. it's name changed from "draft-lentczner-vwrap-foundation" to "draft-ietf-vwrap-foundation" to reflect it's "official" status.
- several people in the working group have voiced concern, however, that this draft does not adequately "layer" VWRAP services on top of HTTP(S). we anticipate a new draft that describes requirements for VWRAP transports in abstract terms, and then describes how LLIDL services are offered on top of HTTP(S). this will include details for caching support and content negotiation when LLIDL resources are accessed over HTTP(S).
- VWRAP : Client Application Launch Message
- this draft defines a MIME type and message format carrying virtual world session initiation information. it is intended to be used by web browsers to launch virtual world clients (viewers.) virtual worlds that use web authentication technologies such as OpenID, OAuth and HTTP authentication may use this message to signal the web browser to launch a client which initiates a virtual world session.
- in mid-2010 members of the VWRAP working group generally agreed that the draft reflected the group's consensus view and was adopted as an "official" draft. it's name changed from "draft-hamrick-vwrap-launch" to "draft-ietf-vwrap-launch" to reflect it's "official" status.
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- VWRAP : Trust Model and User Authentication
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the VWRAP architecture assumes a distributed constellation of servers cooperating to simulate a virtual world. this document describes the trust model hosts may use to determine whether the origin of a request is trustworthy. the specification does not require a host to discard messages without origin integrity, but it does specify how messages carry attestations of inter-domain trust. this draft also defines the agent_login and maintenance resources for VWRAP authentication.
- the previous draft, "Open Grid Protocol : Service Establishment" included the user authentication portion of the draft, but not the discussion of the trust model.
- in mid-2010 members of the VWRAP working group generally agreed that the draft reflected the group's consensus view and was adopted as an "official" draft. it's name changed from "draft-hamrick-vwrap-authentication" to "draft-ietf-vwrap-authentication" to reflect it's "official" status.
- VWRAP : Voice and Text Communication Channel Establishment
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VWRAP is expected to rely on external text and voice communications standards. XMPP is the presumed choice for text communication while RTP is the presumed choice for voice. These specifications do not define locations in a virtual world as addressable endpoints, so this document defines a technique for identifying them for spatial text and voice.
- there are currently no drafts for this specification.
- VWRAP : Agent Presence Establishment
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also known as "the teleport protocol," this specification defines how an authorized user's agent establishes its avatar's presence in the virtual world.
- there are currently no drafts for this specification. previous work on the Open Grid Protocol Teleport specification has been identified as the likely basis for the internet draft.
- VWRAP : Region Description Format
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this document defines the format of the virtual world's scene graph and the protocol interaction used by clients to retrieve it.
- there are currently no drafts for this specification.
- VWRAP : Digital Asset Access
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this document defines the protocol used to request and receive information about digital assets. this specification is not yet written, but is presumed to be based on earlier designs for the Second Life Inventory System and the Simian Grid Asset Server (once known as Cable Beach.) it also defines asset types an implementer MUST support (primitive shapes, textures, etc.)
- there are currently no drafts for this specification.
- VWRAP : Primitive Object Format
- this document defines MIME types and formats for objects in the virtual world: primitive shapes, NURBS and meshes. it is presumed that this documents will specify an extension of existing formats.
- there are currently no drafts for this specification.
- VWRAP : Avatar Format
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avatars are expected to require more detailed information about shape and movement than primitive shapes. this specification describes how primitive objects and (optionally) bio-mechanical skeletal models may be requested by client applications.
- there are currently no drafts for this specification.
- VWRAP : Entity Identifiers
- at the time the working group was chartered, the consensus view was that several "objects" in the VWRAP protocol should be representable by URIs. this document describes how avatars, primitive objects, regions, assets and locations in the virtual world are represented as URIs or URLs.
- there are currently no drafts for this specification.
- VWRAP : Time Sensitive Messages
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some state updates in the VWRAP protocol are considered "time sensitive." that is, they will be useless unless delivered within a proscribed period. object updates and avatar control messages may fall in this category. this document describes the format and semantics of time sensitive messages within the VWRAP protocol.
- there are currently no drafts for this specification.
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supplementary documents
these documents are not specifications, but commentary on the specification, implementation advice or documentation of best practices.
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