Multiplayer implementation in "Halo: Reach"

If you are interested in challenges of multiplayer in AAA titles, here is a very good explanation of the network lag handling in the Halo: Reach game:

P.s. From start to the 57 minutes mark is the most interesting to me. The rest is about measuring, debugging and optimizations, etc.


Some interesting details spotted from the video:

  • Max 16 players in the multiplay
  • One of the client is the “host” (no game server at all?). If the host is disconnected, the clients automatically select the new host. One of the decision parameters is that which client has has the fastest connection
  • The host authorizes the most important events (to prevent cheating)
  • The lag is compensated by:
    • Dividing events into two parts. The first part is done immediately (e.g. the initial arm movement ) to give immediate response on the local client. The second part (e.g. to throw a grenade) is done after authorization from the host.
    • Changing the game mechanics on the host when it receives the event. E.g. activating a shield usually takes a small time before the shield is ready. When a host get the shield activation event request from the client, it substracts the lag from the activation time on host to be able to send authorization faster back to the client.