Networked Game Structure

grazing · 2012-01-29T01:35:19

Hello! I'd like to start by referencing these two threads: http://www.gamedev.n...hrough-gateway/ http://www.gamedev.n..._1#entry1804154 My situation is I, like the above thread starters, have come to a point where I need to decide which path to go. I am using TCP with the servers (Login, Chat, Zones, etc) all running an IOCP. Of the two methods: a gateway or direct connection to said servers (chat, zone, etc) I must say I'm very fond of the gateway implementation, however I have a concern that if the gateway crashes, so do the clients. Referencing WoW or even EQ, you used to be able to connect and if the login server crashed, you would be fine long as you didn't log out. So my question is how did they do it? Without exposing too many sub servers, what would be the best solution? I'm having a hard time wrapping my head around how I would connect to the Login server ,verify the account, and then pass the verified client to the "sub server."(a sub-server is only exposed via a port on the Server Machine to a server higher up in the chain) For example ... login -> verified -> [???] -> connection to [Chat/Server List] -> [???] connect to realm selected. [Login] | V [Chat / Server List] | V [Realm]: -> [Zone] From the second link it is stated you cannot redirect a socket that is already active to a new server, so I would need to close the original socket that was used to verify the client, recreate the socket.and then connect to the sub server. Is this the proper way? How would one ensure that the client was actually verified in the first place? *scratches head* I hope this is something simple that I am making an elephant out of. Thank you for your time!

Networking and Multiplayer Programming

Started by grazing November 13, 2011 10:55 PM

11 comments, last by hplus0603 12 years, 2 months ago

ramdy

141

January 28, 2012 08:27 AM

Yes, you may pay many thousand dollars for this hardware, but when you're at the point where you need gateways and forwarders and whatnot, the leasing cost of this hardware is a very very small part of your budget.

I am thinking in the amazon web services, do you have a favorable opinion about it?
http://aws.amazon.com/ec2/
http://aws.amazon.co...cloadbalancing/

Thank you hplus and ApochPiQ for the time to response, got it clear now.

ApochPiQ

23,138

January 28, 2012 08:16 PM

Designing scalable infrastructures - in pretty much any field, but particularly in networking - is all about contextual details.

What kind of service are you trying to provide? How are requests from clients fulfilled by servers? How frequently do requests come in? What is the ratio of servers to clients expected to look like? What kind of resources does it take to fulfill the average request? Can you segregate request types based on their resource requirements, i.e. put lots of cheap requests on one server and spread out the expensive requests among multiple load-balanced servers?

All these kinds of details are important. I could probably write a huge list of such considerations that go into designing the typical high-scale internet service, and I'm far from an expert on the different models in use in real life systems (my own experience in high-scale systems is limited to a particular subset of technologies).

Without considering all these factors, it's hard to accurately judge the merits of some arbitrary architecture. What you have diagrammed may work excellently for certain styles of service, and completely fall apart at high loads for other types of service. There's a reason why services like elastic cloud computing are middle-of-the-road solutions; they will neither give you optimal performance at load, nor optimal price efficiency on the low end of the scale. (Though to be fair, cloud services are getting pretty darn affordable for most applications these days.)

Services like EC2 have to try and strike a balance between effective use of their own hardware resources and effective scalability for their clients. Someone designing their own network back-end infrastructure is free of such constraints, and can focus on building something that is optimal for their particular needs. And the solutions they deploy are likely to look very, very different.

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hplus0603

11,916

January 29, 2012 01:35 AM

I am thinking in the amazon web services, do you have a favorable opinion about it?
http://aws.amazon.com/ec2/
http://aws.amazon.co...cloadbalancing/

Thank you hplus and ApochPiQ for the time to response, got it clear now.

Yes, Amazon Elastic Load Balancer is one way to achieve load balancing, if you use their Elastic Compute Cloud infrastructure.

enum Bool { True, False, FileNotFound };

ramdy

141

February 03, 2012 09:13 AM

What kind of service are you trying to provide? How are requests from clients fulfilled by servers? How frequently do requests come in? What is the ratio of servers to clients expected to look like? What kind of resources does it take to fulfill the average request? Can you segregate request types based on their resource requirements, i.e. put lots of cheap requests on one server and spread out the expensive requests among multiple load-balanced servers?

Inter process communication between client and server via remote calls, client and server send to each other text strings. There will be several server-services: IRC, Anti cheat, trade, etc. each one with its particular set of scripts.

I am figuring the anticheat service to work like this:
For each action the client affecting the persistent data, once validated by client it will send a text-string to the server in the form: "script_command&param1&param2,..."

For example, if the player buys a potion, it will send to server: "buy_potion&life_potion"

At server side (where the incoming connection is assiciated to a player at login) it is verified if player can buy that potion and have enough money, if so, the operation becomes validated and changes are made to DB (no communication back to client), if operation not validated player is cheating and server will log/disconnect that client.

Another case:
The server want to display a message window to the client: it would send a string to the client in the form: "message_player&A message"
the client receives that string and calls its script "message_player" with the param "A message"

The system is for an MMO Tycoon style game. TCP and just sending strings between client and server for simplicity. I have been digging and thinking how to implement this and this is what I ended with. I think it is very low-bandwitch demanding, in any case, any suggestion is welcome, maybe Im making some mistakes or possible to improve.

Thanks in advance!

Networked Game Structure

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