Distributed Systems II Extremely Massive Multiplayer Browser Based - - PowerPoint PPT Presentation

Distributed Systems II

Extremely Massive Multiplayer Browser – Based Games Νικολάου Σταύρος

Προδιαγραφές 1/5

• Strategy game
• Idea: Tribes(Nomad-like)
• Idea: Tribes(Nomad-like)

Προδιαγραφές 2/5

• Map

– Divided into regions(grid - X,Y coordinates) – Each region has a type(forest, hill, plains, sea, swamps, desert, lakes, mountains) swamps, desert, lakes, mountains) – The type of each region determines resources and movement speed. – Each region has resources(wood, stone, metal, food) – Not distributed – Static(for now)

Προδιαγραφές 3/5

• Tribes 1/2

– Name, population, position(in the map(x,y)) – Move (token which is changes position in the map controlled by players) – Speed:Full, Limited(half speed), Restricted(quarter speed) – Troops

• Units(ID, Type, Quantity, Owner)
• Units(ID, Type, Quantity, Owner)
• Types(Archer, Horseman, Mage, Warrior)
• Upgrades of types above(Ranger, Knight, Battlemage, Gladiator)
• Attributes(ID_type, Name,Att, Def, Requirements)

– Veterans/Trainers

• Units(ID, Type, Quantity, Owner)
• Types: Sentinels(Archer, Ranger), Sorcerers(Mage, Battlemage), Weapon

Masters(Warrior, Gladiator) Paladins(Horseman, Knight)

• Attributes(ID_type, Name, Level, Requirements)

Προδιαγραφές 4/5

• Tribes 2/2

– Actions:

• Move – change position on the map
• Check region – which players are stationed in a specific
• Check region – which players are stationed in a specific

region/part of the world

• Create/Train/Build (troops, veterans)
• Combat(Attack a tribe, Defend against attack, assist a

tribe by attacking its opponent, assist a tribe by defending it)

Προδιαγραφές 5/5

• Tribes (optional)

– Buildings(setlements/facilities - optional)

• Same for each tribe
• Needed in order to craft troops and veterans
• Needed in order to craft troops and veterans
• Very simple as we want nomadic gameplay
• Few(if implemented) upgrades
• Definition(ID, Type, Owner)

Αρχιτεκτονική - Σχεδίαση

• Design decisions

– Multiple Clients – Multiple servers – Single Database – tables collection(no replication) – Distributed Database

System Architecture

Client Client

…

Client Client Client

…

Client Client Client

…

Client

… SERVER Database Shard SERVER Database Shard SERVER Database Shard … …

Αρχιτεκτονική - Σχεδίαση

• Design decisions

– Horinzontal Partitioning

• Method: Shards(Directly Implemented by Hibernate)
• Dynamic number of servers with part of the world’s database.
• Each server will represent a part of the world(with each own tables organized

by (world)region based criteria-this can change)

• 3 –tier architecture
• 3 –tier architecture

– User interface/presentation layer(client will express his actions/querries such as move tribe, troops building, veteran training, combat) – Middle tier/application layer(process clients actions and queries, interact- select, insert, update- with the stored DB and inform the player for the result) – Actual DB/data layer(the data stored in the DB is not in the form that the application layer uses it – it’s stored in relational tables)

Αρχιτεκτονική - Σχεδίαση

• 3 –tier architecture

Client Layer

Web Browser, JSP lient PC Web Browser, JSP

Application Layer

Game Logic, Objects(RMI), Data Access

Database Layer

Tables Clie Web Server

Database Server

Αρχιτεκτονική - Σχεδίαση

• Design decisions

– Language: JAVA – Why:

• Easy
• Easy
• Many already implemented packages/libraries

reduces the code to be written

• Hibernate: Special Java library which offers great

flexibility in managing DB’s based on the relational model(very helpful for RDBMS)

Αρχιτεκτονική - Σχεδίαση

• Design Decisions

– Indexing

• Distributed Hash Tables

– Like hash tables – Like hash tables – The shard/part(therefore the server) of the DB that will be accessed is defined by the return value of the selected hashed function

– Data retrieval

• CAN(hopefully)

Στόχος

• Obviously a playable game
• Database consistency
• Most importantly SCALABILITY!!!