For a stack architecture to be an effective solution two conditions need to be met:
In addition to the article linked in other answers, I can tell a bit about the experience of the Arianne Project. How to keep things synchronized?
Actions are sent from the client to the server carrying user input like walk left, attack monsters 47, say 'hello'. And perceptions are sent from the server to the clients telling them about the state of the world closely around them.
Those perceptions are sent every turn. Depending on the game we use turn times of 30ms to ms.
We have two types of perceptions: A full perception is sent on login and when the player enters a new area zone.
After that differential perceptions are sent including only the modified attributes e. How to work around latency problems? The client does some predictions like smooth walking, collisions checks and so on. But if a client and the server disagree about something, the server wins. The subproject Stendhal a 2D RPG uses a turn time of ms by default with a lot of smoothing done client side.
This makes Stendhal very resistant against lag. Some other games trust the client to some extend to minimize the impact of network lag.
There are two ways which a player with the flag can choose: On in the middle through a tunnel and one on the right sight going up the hill.
So a cheating player runs towards the tunnel, and then causes lag for himself. The server and the other clients will continue to see him running towards it. But after a little time this client can tell the server that it went towards the hill. WoW will check that the distance between the last transmitted coordinates and the current ones fits within the time segment and accept that.
Use of UDP vs. We handled lost packets on our own. This worked perfectly at the early days of the project. But when the server was moved from some home DSL connection to a real data center several years ago, we got huge issues.
The ruleset has to be applied to every single UDP packet. For TCP, however, the ruleset is only applied for the first 3 packets. After that the connection is established.
All following packets will bypass the normal ruleset because they are in the connecting tracking table or because they don't have a SYN flag. How to protect the communication and client from reverse engineering?
Arianne is completely open source, this include the client, server, graphics, music.
And of course that includes our protocol documentation and even an analyzer used for debugging. It is easy to protect the communication against unauthorized sniffing by third parties using SSL. It is, however, impossible to protect it against reverse engineering.
Sure you can obfuscate it and use anti debugging techniques.Thanks for contributing an answer to Database Administrators Stack Exchange! Please be sure to answer the question. Provide details and share your research! But avoid Asking for help, clarification, or responding to other answers.
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