The Analysis And Design Of Game Networking

With the popularization of high-speed access network, more and more Internet users are participating in various interactive multimedia applications. Among these, the most popular are the massive multiplayer online games, or MMOG. In MMOG, a large amount of event data is created by the interactions between various control objects. These event data have different characteristics from that which are generally used on the Internet. Events occur very frequently with short inter-arrival times and their size is quite small because they only contain control information. Most commercial MMOGs use TCP or UDP as the transport protocol for the event data. However, since TCP is such a heavy protocol, due to its complex congestion control algorithm and byte-oriented window scheme, it is difficult to support many concurrent users. On the other hand, UDP has no congestion control algorithm, is not connection-oriented, delivers data by packet, and is a relatively lightweight protocol. It's more suitable for MMOG. But there are no functions available, which permit reliable transmission and session management in UDP. So in this paper, a new application level protocol, Game Transport Protocol (GTP), is designed for the transmission of the event data used by MMOG. GTP supports several functions designed to meet the various requirements of MMPOG. Firstly, GTP uses a packet-based window scheme not a byte-based window scheme as in the case of TCP. This scheme is quite simple and suitable for the small size of the event data. Also, GTP performs session management and supports an adaptive retransmission scheme that meets the time constraints of some event data. Although GTP is a specialized transport protocol, optimized for MMPOG, it could also be used for other interactive multimedia applications.