Two or more computers connected together via cable bound or wireless communication links for the purpose of information exchange.

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76
votes
6answers
17k views

How can I simulate a bad internet connection for testing purposes?

I am developing an online multiplayer game. It works well when I test it on the local area network, but before I release it I would like to test how the user-experience works out for someone who has ...
62
votes
6answers
15k views

How to write a network game? [closed]

Based on Why is so hard to develop a MMO?: Networked game development is not trivial; there are large obstacles to overcome in not only latency, but cheat prevention, state management and load ...
45
votes
8answers
15k views

Is the TCP protocol good enough for real-time multiplayer games?

Back in the day, TCP connections over dialup/ISDN/slow broadband resulted in choppy, laggy games because a single dropped packet resulted in a resync. That meant a lot of game developers had to ...
37
votes
9answers
6k views

How are deterministic games possible in the face of floating-point non-determinism?

To make a game like an RTS networked, I've seen a number of answers here suggest to make the game completely deterministic; then you only have to transfer the users' actions to each other, and lag ...
35
votes
4answers
2k views

Movement prediction for non-shooters

I'm working on an isometric 2D game with moderate-scale multiplayer, approximately 20-30 players connected at once to a persistent server. I've had some difficulty getting a good movement prediction ...
32
votes
8answers
23k views

How can I make a peer-to-peer multiplayer game?

How can I make a p2p multiplayer game? I would like to have a server-less multiplayer game. But then, how all the clients know each other? Why the p2p-protocol is so famous in file transfer but not ...
31
votes
2answers
3k views

How to network this entity system?

I have designed an entity system for an FPS. It basically works like this: We have a "world"-object, called GameWorld. This holds an array of GameObject, as well as an array of ComponentManager. ...
25
votes
5answers
8k views

Lag compensation with networked 2D games

I want to make a 2D game that is basically a physics driven sandbox / activity game. There is something I really do not understand though. From research, it seems like updates from the server should ...
21
votes
3answers
3k views

Why do some networked games use interpolation and some use pathfinding for remote movement?

This is a bit of an open question but I'd like to see someone contribute a good reasoning for both. For a quick example of both: Interpolation Model Think the Valve model where the client is ...
21
votes
9answers
1k views

Techniques to prevent non-official clients in network gaming?

In multi-player network games, what techniques exist to try to ensure that users are connecting with the official client application, and not some hacked client app? I realise there is probably no ...
19
votes
3answers
5k views

How does client-side prediction work?

I've read Valve + Gafferon and hundreds of pages from Google, but for whatever reason I can't get my head around client prediction. To my understanding, the basic problem is: Client A sends input ...
19
votes
4answers
5k views

Best strategy (tried and tested) for using Box2D in a real-time multiplayer game? [duplicate]

I am currently tackling real-time multiplayer physics updates for a game engine I am writing. My question is how best to use Box2D for networked physics. If I run the simulation on the server, should ...
18
votes
9answers
1k views

How do/should MMOs handle disconnection during PvP?

In an MMO (not even necessarily an MMORPG) what are some techniques for dealing with players disconnecting in the middle of PvP? In particular - how do you avoid adversely affecting people who get ...
18
votes
5answers
2k views

Tricks in game mechanics to avoid dealing with network lag compensation?

Implementing network lag compensation is hard, how to avoid it? Maybe it's possible to use tricks and build game mechanics in such a way that lag would be percieved as a non critical or even as a ...
18
votes
9answers
1k views

Real-time Debugging Techniques

There's nothing quite like the routine of tweaking a variable, compiling code that takes a few minutes, executing the code, realizing that your tweak was in the wrong direction and repeating the ...
17
votes
3answers
4k views

How to make a multiplayer game work reliably behind NAT?

Even games that are 100% client/server sometimes have issues when the client is behind NAT. Peee-peer games are even a bigger issues. Some games need to use multiple transports (such as UDP and TCP) ...
17
votes
4answers
2k views

What is involved for a simple UDP game?

I once tried to write a simple game with UDP in a week as a throwaway test. It went horribly. I threw it away early. The main problem i had was restoring the game state of all players/enemies/objects ...
15
votes
5answers
3k views

What is better? Lots of small TCP packets, or one long one? [closed]

I am sending quite a bit of data to and from a server, for a game I'm making. I currently send location data like this: sendToClient((("UID:" + cl.uid +";x:" + cl.x))); sendToClient((("UID:" + ...
15
votes
9answers
6k views

Adding multiplayer to an HTML5 game [closed]

I am interested in making a game that I currently have a co-op experience, however I'm curious as to the best method of implementing this in HTML5. I have made games before using straight C sockets, ...
15
votes
3answers
2k views

Should I keep login server apart from game server?

I'm thinking of making a MMO server, and I've been looking at how other games structure their network. One of the things I've noticed is that there's always a Login server and then the game server(s). ...
15
votes
2answers
1k views

Should the game host be the authority, or another dumb client?

When designing a networked multiplayer-game where one player hosts and others connect, there are two strategies I'm aware of: Have the host-player's game be the authority, with all other players as ...
15
votes
2answers
3k views

What to send to server in real time FPS game?

What is the right way to tell the position of our local player to the server? Some documents say that it is better to send the inputs whenever they are produced. And some documents say the client ...
14
votes
3answers
2k views

How do I efficiently code both the client and server at the same time?

I'm coding my game using a client-server model. When playing on singleplayer, the game starts a local server, and interacts with it just like a remote server (multiplayer). I have done this to avoid ...
14
votes
5answers
3k views

Networking for Real Time Strategy games

I'm developing a real time strategy game for a computer science course I'm taking. One of the harder aspects of it seems to be client-server networking and synchronization. I've read up on this topic ...
14
votes
4answers
761 views

How to protect your real time online shooter from potential bots

I'm looking to create a multiplayer top down shooter. While I've read about different topics, I can see them I've got some real challenges ahead, but I'm all up for it. One thing I can't understand ...
13
votes
4answers
1k views

How can I assign entity IDs in a robust way in a network game?

I'm working on an entity system for a networked game and I'm assigning each entity a unique 32-bit integer id that I can use to serialize references to entities and the entities themselves. Currently ...
13
votes
2answers
578 views

How can I stop the player from drifting due to local input prediction when they stop?

I'm working on a 2D server-client multiplayer game engine (which you can try here). It uses WebRTC DataChannels. (The connections are peer-to-peer, but the host peer still acts as a server.) The ...
12
votes
5answers
3k views

Network layer libraries [closed]

I'm looking for any network layers that are available to add to my game, either free or with fair pricing for indie games. By network layers I mean some sort of library which I can interface with, ...
12
votes
1answer
2k views

Implementing network smoothing

We are making a multipler first person shooter. The client sends it's position to the server at a fixed rate (currently at 10Hz). The server sends a single message contatining all player's positions ...
12
votes
2answers
333 views

Are there tools for testing multiplayer code?

Are there reliable tools that can simulate real life-like network conditions e.g. networks with different bandwidth, different latencies, packet loss etc...?
11
votes
3answers
810 views

I know that my super simple multiplayer setup is probably not a good idea, but why?

I'm making a simple little MOBA just for fun. I was making everything single-player then I realized "oh crap I should probably add multiplayer, huh." I've never done anything with networking before, ...
11
votes
2answers
25k views

How does the 3G network assign IP to smartphones?

I am playing a game on the 3G network using Android or Iphone. Suppose I am moving from one cell to another; Will the IP Address change? If yes, then how can I continue the same game while changing ...
11
votes
3answers
11k views

Best solution for multiplayer realtime Android game [closed]

I plan to make multiplayer realtime game for Android (2-8 players), and I consider, which solution for multiplayer organization is the best: Make server on PC, and client on mobile, all communition ...
11
votes
4answers
2k views

How do you allow networking code to be written in the later stages of the development?

I'm currently in the early progress of writing a game which I eventually will want to improve in most aspects. How can I skip out on writing network code yet leaving it fairly easily implemented, that ...
11
votes
2answers
5k views

What are the networking possibilities with XNA and Xbox 360?

I know that XNA for Xbox 360 has limited access to networking, rumored to only allow communication via a propitiatory Microsoft protocol to other Xbox 360 units. What are the networking possibilities ...
11
votes
3answers
5k views

Javascript and PHP for real-time multiplayer?

I'm wondering if combining Javascript clientside with PHP/mysql serverside is a good idea for HTML5 real-time multiplayer (small scale) browser games? My technical knowledge is very limited, and even ...
11
votes
3answers
1k views

Turn-based board game server references? [closed]

Are there any good references/books to recommend about how to build a turn-base game server? It's something like a chess server for pairing chess players and keep game states. In the past, for example ...
11
votes
1answer
2k views

Should I write my own physics engine, because of networking integration?

I'm currently developing a top down, realtime, zombie shooter. I'm coding this in Java, using JBox2D as my physics engine. I have been coding the networking this week, and am now up to the physics ...
10
votes
3answers
2k views

Is knowledge of hacking mechanisms required for an MMO?

Say I was planning on, in the future (not now! There is alot I need to learn first) looking to participating in a group project that was going to make a massively multiplayer online game (mmo), and my ...
10
votes
3answers
1k views

Prevent players from wallhacking in an online FPS?

Why do we still moan on wallhackers in multiplayer first-person shooters? Isn't it possible to perform occlusion culling for all players server-side? For example, send player xyz information to ...
10
votes
6answers
833 views

Networking Pong Clone

I have the fundamentals of TCP sockets, UDP communication etc, but can't find much on how to apply these to a real time game environment. I have a Pong clone, with 4 players, and need to synchronise ...
10
votes
2answers
627 views

Do I need to implement IPv6 support for my game?

I'm going to implement network features for the game I'm currently working on, now I'm wondering if I need to implement IPv6 support or just having support for IPv4 is enough?
10
votes
4answers
1k views

Run a physics simulation on both client and server?

I'm implementing a multiplayer asteroids clone to learn about client/server network architecture in games. I have spent time reading GafferOnGames and Valve's publications on their client/server ...
10
votes
3answers
2k views

Is there a pattern for writing a turn-based server communicating with n clients over sockets?

I'm working on a generic game server that manages games for an arbitrary number of TCP socket-networked clients playing a game. I have a 'design' hacked together with duct-tape that is working, but ...
9
votes
3answers
950 views

How do I prevent identity spoofing in a multiplayer game?

I'm thinking about clients spoofing IP addresses, tricking other clients that they are the server; that sort of stuff. (I don't know much about this, so if this is completely wrong, please correct ...
9
votes
4answers
384 views

Can packet latency fluctuate?

Can the time it takes for a packet to be transmitted from a client to the server fluctuate?
9
votes
3answers
662 views

How to avoid being throttled?

I'm writing a networked iOS game. When sending packets with GKMatchSendDataReliable (which I assumed was UDP with their own packet reception code written) at 60 packets per second (so 16 ms between ...
9
votes
2answers
2k views

MMO techniques, algorithms and resources for keeping bandwidth low?

Are there any resources and documentation on how current MMOs handle the action and movement data from the compression to the handling on the client? Any resources for movement prediction algorithms? ...
9
votes
2answers
5k views

What are the best ways to serialize and unserialize network messages for C/C++ multiplayer game?

We are using JSON right now and want to move to a binary format for some types of messages between client and server. Should I just read structs into the socket? Use proticol buffers/thrift? How ...
9
votes
2answers
485 views

How to handle entity path-finding and movement in a large networked world?

Considering the image above with tiles split into 32x32 boxes, I have an entity which is marked to 'aggro' nearby players that come close to it. I'd like this monster to ideally chase the player (and ...