End-to-end transmission control mechanisms for multiparty interactive applications on the Internet

Abstract

Abstract-This paper reports on the design and the evaluation of transmission control mechanisms specifically designed for multiplayer, distributed (serverless), interactive Internet applications. Distributed synchronization and dead reckoning are the main elements of this transmission control infrastructure. These mechanisms have been implemented in a fully distributed, multiplayer game application, i.e., one in which each entity in a game session computes its own local view of the session. The role of each entity is consequently to periodically send its own state to all other session participants (using RTP/UDP/IP multicast) and to periodically compute its own local view of the global game state using information received from the other participants. A detailed experimental analysis is provided using MBone and LAN experiments We investigate how the "quality" of the game is influenced by the frequency at which players exchange state information, as well as by network impairments such as packet loss and transmission delay.

The effects of local lag on tightly-coupled interaction in distributed groupware

“…Bucket Synchronization [8], Delta-causality Control [13], and Local Lag [15] are techniques that ensure everyone in the group experiences the same amount of delay, which achieves fairness and consistency between the clients. These techniques include time information in messages, either by separating messages into turns or by including timestamps; the system can then determine when receivers should process those messages to achieve consistency.…”

“…Researchers have suggested several techniques for dealing with network delay in distributed systems (e.g., [4,6,8]). However, most of these techniques are concerned with data consistency -that is, ensuring that the models at different sites contain the same information at the same time.…”

Bounding Inconsistency Using a Novel Threshold Metric for Dead Reckoning Update Packet Generation

“…Remote time-space inconsistency combines both a temporal and spatial inconsistency measure into a single value. It considers the length of time the spatial inconsistency persists, as well as the spatial inconsistency itself [14,15]. In this work, it is referred to as absolute inconsistency.…”

On the support for heterogeneity in networked virtual environment

“…Dead reckoning predicts motion paths in other players' activities and changes in background, generates image frames, and performs convergence if the prediction is incorrect [2,6]. In a situation where players are actively moving, smoothness can be improved by locally predicting the players' activities at a client under limited transmission bandwidth and long end-to-end delay.…”