André Borgqvist MSC2005:20, pp. 50. TEK/avd. för interaktion och systemdesign, 2005.
Virtual environments where users can interact with each other as well as with the environment are today used in
many application areas ranging from military simulations
to massive multiplayer online games. But no matter the
application area, as soon as the number of users reaches a
certain threshold, hosting a virtual environment on a single
machine can become problematic. Speed and quality of the
network connection will limit the number of concurrently
connected users in terms of acceptable visual quality and
hardware requirements of the server will be strict. With a
single point of failure, system reliability could easily be
compromised by means of network or host failure.
Distribution of the virtual environment therefore seems
a reasonable approach in order to address this problem.
Hardware and network requirements would not be so
critical and it would increase reliability by having no single point of failure. Unfortunately distribution introduces new problems dealing with synchronization of the world state within the distribution network.
A possible solution to these problems with the focus on
reliability will be presented in this thesis. The solution uses a peer to peer platform that is able to adapt to changes in the network infrastructure as a base for all communication. To improve synchronization efficiency the network will be dynamically divided into multicast groups based on synchronization needs. The solution will be tested for performance with the network fully functioning and in a
number of more of less broken states to determine the reliability. The results from the tests conclude that the
system is able to perform with what must be seen as acceptable performance levels even in very problematic
network environments. The scalability of the system did
also meet the expectations but the results would have
benefited from more experimentation with larger user