Multiplayer; how does it actually work?

S

SlopeNutter

New member
Ok, we all know the problems with MP. :mad:

But I wonder if soneone can explain to me what actually happens when you do (if you can ;) ) connect, e.g your PC TX's RX's information to what/where then another players computer sends data to ... so that I can understand what actually happens.

Thanks,
Terry
UK
 
Re Multiplay

When it works - you log into a game and you will see someones field allready set up and aircraft usually flying. If the title is p51 only that usually means... well u get the drift..lol

In RL at the field you are patient, and take turns flying you get to have a chat to fellow flyers and congratulate good flying, or some times pick up the pieces of not so good flying..

Well in game You get to talk to others thru chatting, ( takes hands of keyboard and crash usually comes quick - lol ) and thats about it thats sim to rl.

Its a free for all.

My flights were usually filled with picking a plane and trying to avoid wanna be japanese kamkazi's lol.

But it is fun.

And sometimes ( not after school hours ) its very enjoyable - quite a few fly in rl as well as in game.
 
Hi Robert,
Thanks for the reply...what I am after is a technical description of what is going on behind the scenes.
I realise how MP works, i.e learning, playing, chatting and abusing other likeminded flyers planes :D Been playing RF a while now.
I am just interested in the physics of what is happening... when you ask to connect, what actually happens? where does the data go, where is the ap, on the server? What is the server, that kinda stuff.
Cheers,
Terry
UK
 
It,s MAGIC!!!!

Kinda like the thermos mug, it keeps the hot (hot) and the cold(cold).

How do it know ????

kamakazi pilot,
 
Many people here do know
But explaining all of the technical aspects( except maybe about port forwarding) of how multi player works on the internet, does not in any way help any one or effect anything in RF's MP'er
If you want to learn all of the technical aspects on networking I suggest a different forum more suited to that subject :cool:
 
When you connect a two way exchange is established between your computer and the machine acting as the server or host.

Initially during the "syncronization" phase, your computer is instructed as what is to be loaded, and appear on your screen.

Airport info is sent to your computer to be displayed, but planes you do not already have are not transferred to your machine.

The host retrieves positional information on all of the connected players, and also forwards this to each connected client.

In effect the host/server acts as the co-ordinator for all of the connected client machines.

Port forwarding is essential as this is a point to point connection, to each client.
 
opjose said:
The host retrieves positional information on all of the connected players, and also forwards this to each connected client.

In effect the host/server acts as the co-ordinator for all of the connected client machines.

Port forwarding is essential as this is a point to point connection, to each client.
Click to expand...
If everyone only talked to the main server (hosting machine), then only the server would need port forwarding turned on. It almost has to be peer to peer based - meaning that any client can send packets to any other client.
 
I think that it is important to know that there is not a central host/server. There is a list providing the IP addresses of machines currently hosting. The actual work (hosting) is done by the hosting machine and/or the client machines.

If I am wrong, please correct my thinking KE.
 
Spareparts said:
If everyone only talked to the main server (hosting machine), then only the server would need port forwarding turned on. It almost has to be peer to peer based - meaning that any client can send packets to any other client.
Click to expand...

Correct. We currently use a peer-to-peer topology. A basic explanation of how it works is that each client (and host) sends a message to all of the connected players telling them "where" their aircraft is at so it can be displayed at that location in the other players sims. For chat, weather settings, etc. the same system is used - pass a message to everyone telling them what happened. The host is allowed specific privileges to avoid conflicts e.g. everyone changing the airport at the same time.

There are pros and cons to using peer-to-peer as opposed to using a client-server topology which opjose described but generally, client-server provides connection/connecting reliability for the clients and we hope to move to that in the future.
 
With a peer to peer topology... almost unlimited growth is possible (which is a great thing). The users are creating the network used to communicate.

With a server topo, the provider(KE/Great Planes) would have to add capacity as the network grows. This can be great because a T3 connected server could be employed with great power and connectivity. It comes at a monthly cost.

Downside is that the peer topo depends more on the client side resources. There are likely some great client hosts with massive computing power and many lesser hosts. This could be part of the problem along with the quality/reliability of users connections to the internet. Still good broadband and recent computer are enough power for most game needs. With time, and as the people using the software become acclimated to the setup needs, this could be a good way of gaming this application. They are having some hiccups now, but look to be well on their way to solving them and getting the word out.
 
Last edited:
wjkssmd said:
With a peer to peer topology... almost unlimited growth is possible (which is a great thing). The users are creating the network used to communicate.

With a server topo, the provider(KE/Great Planes) would have to add capacity as the network grows. This can be great because a T3 connected server could be employed with great power and connectivity. It comes at a monthly cost.
Click to expand...
When he says client-server, I think he's still referring to a non-KE related server, meaning that the hosting machine is the server.

You are correct in the fundamental difference though in that peer-to-peer scales better than client-server. With a central server, you need a faster machine to host as well as a higher bandwidth network connection. I have no feel for how many packets are exchanged, so its hard to say what the load may be. A lot of games have the ability to launch a pure server, where someone dedicates one machine to being the server and runs their own client on a second machine. This gets around the faster machine issue, but not the network bandwidth issue.

I haven't been paying too much attention, but given the description of how it works, I'm surprised that people without port mapping turned on can affect the rest of the cluster. If they only use UDP, and updates are sent to a client using UDP without port mapping, then I would have thought that only that client would have been affected. I guess they use TCP or maybe they require some sort of handshake to try and recover from packet loss.
 
Thanks chaps for taking the time to explain rather than the usual 'look on another forum' dross. I am sure other readers of the forums will be interested.

So, am I right in assuming then that as peer to peer. the performance of the server (person who initiates the m/p in this case) dictates the overall performance of the m/p experience?
If so, that would lead me on to thinking that as I am in the UK and my ISP is not really good at Peer to Peer i.e the up/dn speeds are horrendously slow compared to you lucky buggers over the pond it might sod things up a bit :confused:

Also there are occasions when I use satellite for internet from ships, although the speed is good up/dn, the latency I think is around 650mS...and I could not connect at all to any m/p...any thoughts?

Cheers,
Terry
UK
 
I've MPed with people from Australia, Russia and France before. I saw no latency/lag issues. I've MPed with a guy from Cincinnati, OH (60 miles- 100 km from me) and did see latency/lag issues. If you have a good connection to the internet, you should be fine. I've heard in the past that satellite is not to good for mp anything, for the reason that you mentioned. I've also seen where a session goes great, until a person joins who is not properly configured as far as ports go, and brought the whole session down. What is your MP performance like?
 
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