This report presents results from the analysis of the Quake III Arena source code in order to gain insights into how the packets flowing between server and client are constructed. The server to client packets contain game state information that is based on the aggregation of the changes in state of the individual game entities in the vicinity of the player, whilst the client to server packets contain information of the changes in the individual players' state. Ultimately the information sent affects the size of the packet and may be used as a basis for determining network performance characteristics of the game or for creating modifications to the source code. Quake III Arena is seen to employ both delta states to incrementally updates changes in the game from an initial baseline and Huffman coding. These techniques have the effect of minimising the size of packets, and so improving the networking performance. Quake III Arena is programmed largely in the C programming language and heavily employs the use of ''C structs'' to store information on various items within the game.