Category Archives: Reference

Information that is intended to be used to support or augment other content on this site. May include or link to content from external sites.

Glossary

Reference
Game Server Architecture Patterns

Game Server Architecture Patterns

Pattern, Reference, , , , , ,

This page presents a collection of multiplayer game server architecture patterns that describe solutions to common problems in multiplayer game server development. Over time, I hope to build a library of patterns based on real-world experience, research and experimentation by game server developers.

Pattern: Map-Centric Game Server

Posted: October 27, 2015

Problem How do we distribute the load of running core game play functionality across multiple processes to support thousands of concurrent players? Context We are developing the server for a massively multiplayer online game with a client-server architecture. The game design seeks to create an immersive play experience by enabling thousands of players to interact with each other in a … Continue reading Pattern: Map-Centric Game Server →

0 comments

Pattern: Responsibility-Oriented Game Server

Posted: December 3, 2015

Problem How do we distribute core game play load across multiple processes in a way that supports flexible scaling and efficient allocation of computing resources? Context We are developing the server for a massively multiplayer online game with a distributed architecture. The game design seeks to create an immersive play experience by enabling thousands of players to interact … Continue reading Pattern: Responsibility-Oriented Game Server →

17 comments

Pattern: Seamless World Game Server

Posted: March 8, 2016

Problem How do we create a game server that permits unlimited freedom of movement and game play on an expansive map with no apparent boundaries? Context We are developing the server for a massively multiplayer online game with a client-server architecture. The game design seeks to create an immersive play experience by enabling thousands of players to interact with … Continue reading Pattern: Seamless World Game Server →

7 comments
Mysterious Monoliths by John Picken

Pattern: Monolithic Architecture

Posted: October 1, 2015

A description of the Monolithic Architecture pattern as it applies to multiplayer game server architecture.

1 comment
Vodafone Innovation Park Labs

Pattern: Distributed Network Connections

Posted: October 7, 2015

Use the Distributed Network Connections pattern to maximize the number of connected clients with minimal impact on game server performance.

0 comments
Me balance cookeys

Pattern: Client Side Load Balancing

Posted: October 15, 2015

Problem How do we ensure a balanced distribution of client connections across a set of connection servers in a distributed game server architecture? Context We are developing the server for a massively multiplayer online game with a client-server architecture. The game design seeks to create an immersive play experience by enabling thousands of players to connect simultaneously … Continue reading Pattern: Client Side Load Balancing →

0 comments

If you have feedback, corrections, or questions about any of the patterns you see at Engines of Delight, please leave a comment on this page, or any of the specific pattern posts.

Featured image flickr photo shared by Dvortygirl under a Creative Commons ( BY-SA ) license

Resources

Reference,

This page is a collection of various resources relevant to the topics discussed on Engines of Delight that I’ve found to be useful or promising. If you have suggestions for adding other resources, or feedback about the ones already listed, please leave a comment on this page.

Thanks for playing!

TWD: No Man's Land is Next Games' most recent mobile MMO.

[Podcast] Hanselminutes: Scaling The Walking Dead: No Man’s Land

Posted: April 5, 2016

Scott Hanselman talks with Next Games’ CTO, Kalle Hiitola, about the server architecture of their newest game, The Walking Dead: No Man’s Land. This is a great opportunity for those of us interested in game server development to learn from others’ real-world experience.

0 comments

[Presentation] Building Scalable Stateful Services

Posted: November 3, 2015

I was researching stateful distributed systems for an article today and found a post on High Scalability that was a perfect fit. It’s an unofficial transcript of a StrangeLoop 2015 talk by Caitie McCaffrey, Tech Lead for Observability at Twitter. I read the transcript first, then felt compelled to watch the presentation.

0 comments

[Discussion] A Journey Into MMO Server Architecture

Posted: October 26, 2015

I discovered this post today while doing some research for another post I’m writing. It’s about the server architecture of the sci-fi MMO sandbox game, Face of Mankind: Fall of the Dominion, published by Nexeon Technologies. The post is a couple of years old, but I think the topics are still important. Sadly, the game was recently shut down. However, … Continue reading [Discussion] A Journey Into MMO Server Architecture →

0 comments

[Podcast] SE-Radio: Rebecca Parsons on Evolutionary Architecture

Posted: October 14, 2015

The concept of evolutionary architecture is a good fit for game server development. Game servers are complex enough to warrant a disciplined focus on building a good architecture. Yet, game development is very subjective, and making a great game is an exercise in evolution. The five principles of evolutionary architecture discussed in this podcast can help us in evolving a solid game server architecture.

0 comments

[Discussion] Ultima Online Server Architecture

Posted: October 4, 2015

I recently ran across a Quora discussion from a few years ago about the technology stack of Ultima Online’s original servers. In it, a few of the game’s developers recall some of the game’s early server architecture decisions and their outcomes. It’s an interesting read with some good real-life insights. Source: What was the technology stack … Continue reading [Discussion] Ultima Online Server Architecture →

0 comments

[Podcast] SE Radio: Software Architecture Sketches with Simon Brown

Posted: September 22, 2015

Podcast Summary Simon Brown, author of Software Architecture for Developers, talks with Sven Johann about using Software Architecture Sketches to visualize, communicate and document software architecture.

0 comments

[Podcast] SE Radio: Stefan Tilkov on Architecture and Micro Services

Posted: September 22, 2015

Podcast Summary Micro services is an emerging trend in software architecture that focuses on small, lightweight applications as a means to avoid large, unmaintainable, monolithic systems.

0 comments

[Podcast] DotNetRocks: Marc Mercuri and Mark Simms Build Resilient Cloud Applications

Posted: September 22, 2015

Podcast Summary Carl and Richard talk to Marc Mercuri and Mark Simms about resilient cloud architecture. The conversation starts out focused on the white paper called ‘FailSafe’ and the guidance it provides for building resilient cloud applications – but the information is applicable to any large scale system running on any sort of infrastructure.

1 comment

 

 

Know what to Build: Assessing Impacts for MMORPG

Article, Reference, ,

Assumptions for MMORPG Feature Impact Assessment

The feature impact assessment for the MMORPG game design requires a number of assumptions that aren't documented in the main posts or in the "reference problem statement" for the game. I've provided them here to serve as a rationale for impact rankings that I chose.

 
FeatureSizeComplexityImportance
Persistent item state
Rank: 5
Ubiquity and importance of items will make for large numbers in inventories and various game systems. Expect high frequency of both reads and writes. Caching definitely going to be needed. Again, Redis perhaps.
Show more
Show less
Rank: 5
Huge variety of items with modifiers/enhancements/persistent effects means key/value store over table storage. Also, BLOBs not worth the trouble; too likely for object attributes to change.
Economy, player trades, missions and other use cases where items are transferred between owners will require transaction support.
Show more
Show less
Rank: 5
Item-based systems are at the core of the game. We must handle this.
Show more
Show less
Large shared world
Rank: 5
Multiple shared spaces roughly 100 sq km. Intended to support average 3000 players / map (30 / sq km). Populated areas will max 200 players / sq km in non-combat activity. Battleground and raid areas max 100 players / sq km with combat activity during events.
Show more
Show less
Rank: 5
Using non-contiguous shared maps, with instanced spaces for certain missions and group activity. Will need lots of testing and iteration of visibility vs. performance using various terrain geometry scenarios. Also, need to do serious investigation on NPC populations vs. players. Probably need some "clever tricks" to make things feel right.
Show more
Show less
Rank: 5
We have flexibility on how to achieve it, but we must have the "feel" of a large world with lots to do.
Show more
Show less
"Items are important
and ubiquitous"
Rank: 4
Items are second only to character, but without items you really don't have much character. Inventory will be massive; nearly all game systems will interact. Lots and lots of state updates on the server; hopefully somewhat minimizing transfers to client.
Show more
Show less
Rank: 5
What can I say? Items touch everything: combat, crafting, economy, visuals, missions, and world interaction.
(repeated from character visuals) Need a good - no, great - visibility and distance culling system. Also may need server-side LODs (not graphical, but governing number of item slots that may be visible to others). Need to work with client devs on pre-caching of items in the client. Also need general item/object catalogue for classifying what objects can be seen at what locations and/or with which NPCs to minimize load, because we can't really do that with Player characters.
Show more
Show less

Rank: 5
Essential to game play. The only wiggle room is probably in variety of items, but it won't be enough to really limit load. We have to get this right.
Show more
Show less
Unique character visuals
Rank: 4
Large number of players * (Body Mod Slots + Character Creation Choices) = lots of stuff.
Mitigated a little by client-side pre-cacheing, and a little more by aggressive server-side distance culling.
Show more
Show less
Rank: 5
It will be a challenge to get the variety we'd like without overwhelming bandwidth with state updates.
Need a good - no, great - visibility and distance culling system. Also may need server-side LODs (not graphical, but governing number of item slots that may be visible to others). Need to work with client devs on pre-caching of items in the client. Also need general item/object catalogue for classifying what objects can be seen at what locations and/or with which NPCs to minimize load, because we can't really do that with Player characters.
We have to insist that all behavior/game play item stuff is fully decoupled from the visual stuff so we can aggressively fall back if needed.
Show more
Show less
Rank: 3
Fortunately design and art is willing to give ground here. We want as much as we can get within reasonable tech limits. Plus, this is an area that's great for expansion after ship.
Show more
Show less
Large number of players
Rank: 5
We want thousands of concurrent users. This drives all aspects of scale in all systems. Need careful attention to data serialization and network optimization at the low level.
State updates will be constant, both between server and clients and also between server-side processes, and persistent storage.
At higher levels, we need to distribute load laterally across an undetermined number of services and hosts. This will also require the ability to scale laterally as well. No single points of failure or bottlenecks, please!
This is what puts the "M" in MMO.
Show more
Show less
Rank: 3
We need to scale, but we can make design concessions to get it. Distribute load based on functional responsibilities, orthogonal to game play and world geometry. Consider actor model for ease of single-threaded-ish implementation.
Show more
Show less
Rank: 4
Essential to be massive; but not essential to hide partitioning/sharding from players. Who wants to get to know that many people anyway?
Show more
Show less
Persistent mission state
Rank: 3
Lots of data, but modified infrequently. Reasonably easy to optimize loading of a subset at any given time.
Show more
Show less
Rank: 4
Mission data is almost surely graph-based. Note fairly tight integration with items and other systems that use them; need to make sure we cleanly decouple mission and item state. Probably key/value store, *maybe* BLOB if absolutely necessary, but try (hard) to avoid. Versioning essential from the start; don't cobble it on later.
Show more
Show less
Rank: 4
MMORPG, y'all. Story-based missions are where it's at.
Show more
Show less
Persistent character state
Rank: 3
We can keep this fairly tightly scoped if we do it right. Most integration between characters and other game systems is above the persistence layer. Need to scale frequent writes, infrequent reads (assuming cache).
Show more
Show less
Rank: 3
Probably some kind of key/value store for attributes. BLOBs seem attractive at first, but IMO they'll bite you in the ass later. Basic CRUD operations with a write-through cache on top - Redis, anyone?
Show more
Show less
Rank: 5
If we don't get this right we need to go home.
Show more
Show less
Text and voice chat features
Rank: 3
Text chat is fairly straightforward to scale up. Voice chat is a bigger challenge; consider a third party solution or cloud service only.
Show more
Show less
Rank: 2
Chat tech is generally well understood, with support from existing solutions if desired.
Integration with game features will be limited to global, regional, alliances, party, and private channels.
Just don't try to implement a custom XMPP server! Not worth it.
Show more
Show less
Rank: 4
This is an MMO; we need people to interact and build community in the game. Need this for ship.
Show more
Show less
Persistent alliances
Rank: 2
I'm arbitrarily deciding that alliances will be pretty tightly scoped. It will be focused almost exclusively on supporting social interaction and offline coordination of group play. Not tightly integrated with other game systems.
Show more
Show less
Rank: 3
Limited scope limits complexity automatically. Mostly basic table-oriented persistence required; small number of push notifications e.g. player joined/left, fairly basic tech.
Show more
Show less

Rank: 3
This is a feature that we can enhance after we launch the game. Deferring this until we have more players and a greater need for social integration is a reasonable tradeoff.
Show more
Show less

Return to Know what to Build: Assessing Impacts.

Multiplayer Game Types

Reference
TypeDescriptionPlayersPersistenceGame Examples
FPSFirst person shooter<= 256 NoQuake 2
Unreal Tournament
Counter Strike
Battlefield
Call of Duty
Tribes: Ascend
M.A.G.
RTSReal-time strategy game<= 8NoCommand and Conquer
StarCraft
WarCraft
Homeworld
MMO
Massively multiplayer online gameThousandsYes, generallyEve Online 1)Eve Online describes itself as "an open-ended Massively Multiplayer Online Game (MMOG)." It does not fall cleanly into one of the more specific types below so we'll just call it an "MMO" for now - https://wiki.eveonline.com/en/wiki/About_EVE_Online
See more specific MMO examples below.
MMORPGMassively multiplayer online role-playing gameThousandsYes, character development, items.Ultima Online
EverQuest
World of Warcraft
Guild Wars
Rift
Elder Scrolls Online
MMORTSMassively multiplayer online real-time strategy gameThousandsYes, player bases, leader boards.Shattered Galaxy
Battle Pirates
War Commander
Tiberium Alliances
MMOFPSMassively multiplayer online first person shooterHundreds to thousandsYes, character development, items, leader boards.Planetside
Firefall
Defiance
Global Agenda
MOBAMultiplayer online battle arenaLeague of Legends
Defense of the Ancients
Smite
AirMech
SandboxMultiplayer sandboxYes, player and world stateMinecraft
MMOSMassively multiplayer online sandboxYes, player and world state.Trove
Roblox