Building Scaleable Middleware for MMORPGs

CowboyRobot writes "ACM Queue has an article exploring the challenges of developing a reliable platform for an MMORPG, specifically looking at Wish by Mutable Realms. From the article: 'A common scalability problem for distributed multiplayer games relates to managing distributed sets of objects... A player may not be a member of more than one guild, or a guild may have at most one level-5 mage (magician). In computing terms, implementing such behavior boils down to performing membership tests on sets of distributed objects.'"

Comments

MMORPGs need better real-time characteristics

[Bryan Ischo]

I've tried a few MMORPGs and have found them all to be lacking in the same key area: one's control over one's character is not real-time. This is a generic description of a problem which surfaces in many ways in MMORPGs, most notably in the combat system. I haven't found one yet that allows real-time combat; it's always "click on the guy you want to fight and press the 'attack' button", then sit back and watch. Typically can do things like cast a spell or use a buff or otherwise make strategic changes to the way that your character is fighting, but you can't aim, run around, swing at the monster, etc, as you can with first person games.

The game that comes closest to the combat system I would want is Jedi Academy, in which the multiplayer mode works just like the first-person real-time perspective of the single player game. You do have to aim, you do have to run around and avoid shots, you do have to swing your light saber yourself. I find this to be infinitely more enjoyable than the MUD-like "you hit the spider for 10 points, it hit you for 5 points" back-and-forth that is common on all of the MMORPGs that I have played.

One gets the feeling in playing these MMORPGs that your client view of the world only loosely approximates what is happening on the server. You can make your character run from here to there and find that other people are "sliding" by or popping in and out as you get only sporadic notification from the server of what's really happening. It all gives a very disconnected feel that I really find unappealing about MMORPGs.

There must be some kind of scaleability limitation though because Jedi Academy only supports about 30 players or so at a time in an area that is far smaller than a play area in an MMORPG. I think that if someone could design an MMORPG that played like an FPS, but had all of the depth and breadth of one of these not-so-real-time MMORPGs, it would be ideal.

As an aside, has anyone beta tested Worlds of Warcraft? It like an excellent execution of the MMORPG genre, but I have yet to read any comments from beta testers on whether or not the fighting is real-time or "faked" like other MMORPGs is ...

Re:MMORPGs need better real-time characteristics

[Dodger73]

This burns down to the scalability problems the article is mentioning. Real-time characteristics always mean more frequent transfer of potentially larger data packages, and the more frequent processing of those packages. While you may be able to run Jedi Academy with 30 players on a cable connection, the same is not necessarily true for 300 players.
There are ways to at least make bandwidth and processing requirements scale less than linearly with the numbers of players, but the actual problem persists. The more players, the more data. The more data, the more bandwidth requirements and the more latency. The more latency and bandwidth requirements, the more the realtime characteristics suffer. Needing halfways reliable security (read: hack protection) methods doesn't make it any easier.

It is not only the reason why MMOs aren't realtime like an FPS, but also why FPSs aren't MMP like MMOs ;)

Re:MMORPGs need better real-time characteristics

[Surlyboi]

There must be some kind of scaleability limitation though because Jedi Academy only supports about 30 players or so at a time in an area that is far smaller than a play area in an MMORPG.

You hit the nail on the head with the scalability issue. Unless you're playing a game like Planetside where there's no significant penalty for dying, (other than just having to respawn and grab more gear) you're going to have a lot of unhappy players who get 0wned by the LPB twitch freaks.

I think that if someone could design an MMORPG that played like an FPS, but had all of the depth and breadth of one of these not-so-real-time MMORPGs, it would be ideal.

I agree, it would be spectacular. But as it is, there're a ton of people playing SWG who'll just spam damage on players as they load into new zones. Unless everyone in the world is on the same footing connection-wise and the ganeworlds are seamless; a real-time implementation of a combat system would only compound this kind of grief play.

Re:Scalability and joining guilds

[Anonymous Coward]

This problem is in no way limited to MMORPG, the problem of authenicating and managing objects across multiple servers/clients is central to all online games. As a hobby games developer with a pretty good understanding of this I suggest you read Policing Online Games and then compare the conceptual pitch to issues in digital cash and online money transfers etc.
These ideas also overlap with the much hated and draconian 'trusted computing' models.

Enforcing a set of rules across a network of untrusted hosts is a fascinating problem. For example Gnunet and Freenet forgo a centralised trust agent and allow trust to emerge from the interaction, and recorded past behaviour, of individual nodes.

Digital 'trust' is sure to remain a huge area of interest. However it will also continue to be an area dominated by soothsayers, witchdoctors and charlatans because it contains a numer of fundamental logical problems which are not solved in the traditional human way of appeal to authourity.