Server Network Architecture

[lakedoo23]

I am exploring different options for a game I want to create and was wondering if someone had information on the network architecture of the eqemuServer client / server, I am going to dig into the code to see how it works hopefully. However I was wondering if there was some documentation floating around that shows how the player / npc positions are input and updated? Just a cursory look, it seems like the client sends a position update to the server ~4 times a second and the server checks to see if the player is within a radius permissible based on velocity and previous position, otherwise they are flagged as cheating. Thanks in advances, hopefully this isnt too off-topic.

[Uleat]

Once you get get past the initial handshake, it's pretty much event-driven..with a few exceptions like you noted.

I assume you've already found this: https://github.com/EQEmu/Server/blob...ent_packet.cpp

On the out-going side..there's really not much coherency. Packet creation could be any where there is access to a data
stream.


To complicate things, we support multiple clients..with each having a chance of added/removed features and different
payload formatting.

If possible, we try to format server data structures to represent one of the clients.

When that's not possible, a 'hybrid' format is usually employed.


As far as documentation..there really is none.

Our wiki (http://wiki.eqemulator.org/i?M=Wiki) is really setup for user/admin/content developers, not code developers.

This base code has been around for over a decade and most contributors are (have been) part-time volunteers.


If you have specific questions, you can post them in the forums, or hop on irc and see if you can get a response there.

[lakedoo23]

Thanks for the reply Uleat, I will do some more research with the links you provided.

[Uleat]

I should have noted that you can activate certain portions of the logging system to view things in real-time..like incoming/out-going
packets (with opcodes.)

I think #log will give you a help description of the flags.

[Zaela_S]

The server netcode is a bit of a mess to read. I made a start at a client networking library a little while ago that you might find a bit easier to follow. Doesn't have many of the details filled out (basically all it can do at this point is connect to a server masquerading as your client of choice, then send some chat messages and not much else) but the fundamentals are there. Socket -> Ack Manager -> Protocol Receiver probably the best places to start.

One thing I'd like to say about EQ's networking is that it kinda sucks. Plenty of one-off oddities and conditionally-present flags that seem like things that crept in over time and were never properly incorporated into the design. Could have saved some headaches if they just reserved an extra byte or two in the per-packet header for some 1-bit flags.

[lakedoo23]

I am creating a game from scratch, thinking C# / lidgren (network library) for the server and using Unity for the front end, I love the way that the EQ Emu Server and client work together for movement of players and NPCs and wanted to use something similar using eqemu as a model, not to mention it seems to have lasted the test of time with the same design / architecture. Hopefully I can learn from what eqemu has without the issues, errr not issues that are the eqemu fault, the issues induced to help it be compliant with the client.

[Shendare]

I can see where you're coming from, wanting to take advantage of what the various employees and volunteers have learned about client/server communications over the years of EQ's and EQEmu's development, while hopefully avoiding the pitfalls that come from so many different people with different ways of thinking working on it over time.