http://blogs.unity3d.com/2014/05/12/announcing-unet-new-unity-multiplayer-technology/
A few weeks ago, at
our Unite Asia conferences, we announced that we are developing new
multiplayer tools, technologies and services for Unity developers. The
internal project name for this is UNET which simply stands for Unity
Networking. But our vision goes well beyond simple networking.
As you
all know, the Unity vision is to Democratize Game Development. The Unity
Networking team wants to specifically Democratize Multiplayer Game
Development. We want all game developers to be able to build multiplayer
games for any type of game with any number of players.
Before joining Unity, members of the
networking team worked mainly on MMOs such as Ultima Online, Lord of the
Rings Online, Dungeons and Dragons Online, Marvel Heroes, Need for
Speed Online and World of Warcraft. We have a lot of passion for and a
ton of experience with making multiplayer games, technology and
infrastructure.
The Unity vision was known to each of us and was always
very appealing.
When the chance to do something truly great like
specializing the Unity vision with multiplayer came up, it was
impossible to decline. So we all left our former jobs and joined Unity
to make this vision happen.
Right now, we’re working hard to deliver
these tools, technology and services so anyone can make their own dreams
of a multiplayer game a reality.
This is of course a pretty big
undertaking, but, like I said, we have all done this before, and we are
all very driven to do it again (because it’s really, really cool!). The
way we have tackled this is to divide our overall goal into phases
which should be familiar to Unity developers.
We take the approach of
releasing a Phase 1, getting feedback from our users, adding that
feedback to our work to make the next phase even better and repeating
that cycle.
For UNET, Phase 1 is what we
call the Multiplayer Foundation – more on that in a bit. Phase 2 is
where we build on Phase 1 to introduce server authoritative gaming with
what we call the Simulation Server, we’ll blog about this later.
Finally, Phase 3 is where we want to introduce the ability to coordinate
multiple Simulation Servers through a Master Simulation Server.
As
usual, exact dates for this are not possible and of course things can
change, especially after gathering feedback from our users. But we can
say that Phase 1 will be part of the 5.x release cycle and Phase 2 is in
R&D right now.
So what do we mean by the Multiplayer Foundation for Phase 1? The main features are as follows:
-
High performance transport layer based on UDP to support all game types
-
Low Level API (LLAPI) provides complete control through a socket like interface
-
High Level API (HLAPI) provides simple and secure client/server network model
-
Matchmaker Service provides basic functionality for creating rooms and helping players find others to play with
-
Relay Server solves connectivity problems for players trying to connect to each other behind firewalls
We had some inherent
limitations with our legacy system that we needed to address and with
our greater goal in mind it became clear that we needed to start from
scratch. Since our goal is to support all game types and any number of
connections, we started with a new high performance transport layer
based on UDP.
While it’s true that a lot of games are done quite well
with TCP, fast action games will need to use UDP as TCP holds the most
recently received packets if they arrive out of order.
From this new transport layer
we built two new APIs. We have a new High Level API (HLAPI) which
introduces a simple and secure client/server networking model. If you’re
not a network engineer and you want to easily make a multiplayer game,
the HLAPI will interest you.
We also wanted to address feedback we’d
received on our old system: some users needed to have a lower level
access for greater control. So we also have the Low Level API (LLAPI)
which provides a more socket-like interface to the transport layer. If
you are a network engineer and want to define a custom network model or
just fine tune your network performance, then the LLAPI will interest
you.
The Matchmaker service is used
to configure rooms for your multiplayer game and get your players to
find each other. And finally the Relay Server makes sure your players
can always connect to each other.
We know from our prior
experiences that making multiplayer games involves a lot of pain. So
the Multiplayer Foundation is a new set of easy to use professional
networking technology, tools and infrastructure for making multiplayer
games without this pain.
To even get started, I think it is fair to say
that making a multiplayer game requires a fair bit of knowledge of
networking and protocols. You either overcome the painfully steep
learning curve yourself or find a network engineer to join you.
Once
you’ve gotten past that, you then have to solve the problem of getting
your players to find each other. And once you’ve solved that problem,
you now have to deal with getting players to be able to actually connect
with each other, which can be troublesome when they are behind
firewalls with NAT.
But then if you’ve solved all of that you’ve
created a bunch of associated infrastructure which wasn’t game
development and probably wasn’t fun. And now you have to worry about
dynamically scaling your infrastructure which usually takes a bit of
prior experience to get right.
Our Phase 1 addresses each of these pain
points.
The HLAPI eliminates the need for a deep knowledge of
networking. But the LLAPI is there if you are a network engineer and you
want to do things your own way.
The Matchmaker solves your problem of
getting your players to find each other.
The Relay Server solves your
problem of getting players to be able to connect to each other.
And we
also solved your problem of the associated infrastructure and
dynamically scaling it.
The Matchmaker and Relay Server live in Unity’s
Multiplayer Cloud. So not only do the physical servers scale up and down
based on demand, but the processes scale up and down as well.
We are very excited about UNET
and are eager to share more details. Over the next few weeks we’ll
follow up with more blogs from the rest of the team. We would love to
hear what you think, and we can’t wait to see what you all make with
this in the future.
Everyone
wants to be Harry Dresden. Except maybe Harry Dresden. And people who
haven’t read Jim Butcher’s Dresden Files books, in which case, get thee
hence to a bookstore! 
