Figu re 1: U ser Inte rface fo r Sha red V irtual W orld MVIP-II: A Protocol for Enabling Communication in Collaborative Virtual Environments Dr. John Robinson CRC Canada 3701 Carling Avenue Ottawa, Canada +1 613 990-9456 john.robinson@crc.ca Sarah Dumoulin CRC Canada 3701 Carling Avenue Ottawa, Canada +1 613 990-5242 sarah.dumoulin@crc.ca John Stewart CRC Canada 3701 Carling Avenue Ottawa, Canada +1 613 998-2079 john.stewart@crc.ca ABSTRACT This paper presents the second edition of our multicast protocol designed to enable shared v irtual worlds. This secon d release was u nderta ken to prov ide an i n t er a c ti o n methodology with other participants of a shared virtual world. These virtual world participants can be either human-controlled, or algorithmically co ntrolled conten t delivery avatars. Categories and Subject Descriptors C.2.2 [Netw ork P rotoc ols ]: Applications - Multicast IPv.4 Shared Virtua l Env ironm ent pro tocol. G e n er a l T e rm s Algorithms, Performance, Design, Reliability, Experimentation, Langu ages. Keywords Virtual Reality Markup L anguage (VR ML), distributed virtual environm ents, multiu ser virtual reality, autonom ous avatars, IP Multicasting, Mbone. 1. INTRODUCTION Interest in shared virtu al worlds has been ev ident for som e years, notably in the development of Distributed Interactive Simluation (DIS) and the H igh Lev el Architecture/Run Time Infrastructure (HLA /RTI) by the Defense Advanced R esearch Projects Agency (DARPA) and the US D epartment of Defense. At the same time, VRML has emerged as an approach for the 3D Web and parallel methods to network and share such a virtual world are being developed [1]. To contribute to the development of shared VRML, b u i l d in g on concepts from th e c li e n t- s er v e r based VRML interchange protocol used by the V net [2], a shared multicast virtual world protocol, MVIP was prop osed [3] and presented at the Web3D Organizations Web3D - VRML 2000. The original goal of MVIP was to replicate multicasting conferences as would be experienced using tools such as V IC [4], 155 Copyright © 2003 by the Association for Computing Machinery, Inc. Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from Permissions Dept, ACM Inc., fax +1 (212) 869-0481 or e-mail permissions@acm.org. © 2003 ACM 1-58113-644-7/03/0003 $5.00