Reliving the history of multi player games @phuesler @rirei At - PowerPoint PPT Presentation

Reliving the history of multi player games @phuesler @rirei

At Wooga Evolution is driven by teams

Technologies

Architecture

Platforms

User interaction

Level 1: Read-only interaction

High score Pacman

read-only access Client Client DB Score

Level 2: Inbox interaction

Turn based Empire Civilization

inbox Client Client DB Inbox

Inbox interaction Client Client App Inbox

woo.ga/backend

Level 3: Real interaction

Real interaction MUD World of Warcraft

Real interaction Client Client Usr Usr App Loc

Handling conflicts Client Client Usr Usr Log Log App Loc

woo.ga/backend

Level 4: Real time interaction

Real time interaction Super Mario Kart Starcraft

Player 1 Player 2 Server

Player 1 Player 2 Server

Player 1 Player 2 Server

Sources of inspiration

We depend on • good throughput • low latency • low packet loss • no jitter

Level 4: Real time interaction on mobile

3G Internet

Bandwidth 0.73 Mbps 3G 1.2 Mbps https://de.wikipedia.org/wiki/High_Speed_Uplink_Packet_Access https://de.wikipedia.org/wiki/High_Speed_Downlink_Packet_Access

Added Latency (RTT) * 3G 70 - 180 ms * HSDPA/HSUPA http://202.194.20.8/proc/VTC09Spring/DATA/09-18-19.PDF

Packet loss

Latency Jitter 300 225 150 75 0 RTT ms

Let’s do Bomberman

Real Time Interpolation Lag Compensation Lockstep Packet Loss Quality of Service TCP UDP Client Prediction Peer-To-Peer Latency Object Replication Synchronization Protocol Physics Extrapolation Match Making Collision Detection

1

Architecture C1 Server C2 move :up c1 moved :up c2 placed bomb place bomb bomb exploded bomb exploded game over game over

TCP JSON EASY!!!

Works on Wi fi : )

game doesn’t work on 3G : (

Jitter

Dropped packets

TCP Packet Ordering and Resend

TCP Flow and Congestion Control

no update no update Warping no update 4 updates at once

or WORSE : (

2

Architecture C1 Server C2 move :up c1 moved :up c2 placed bomb place bomb bomb exploded bomb exploded game over game over

3G UDP Will it work?

Poor man’s TCP User Id Local Seq No Remote Seq No Ack bit fi eld JSON P N Payload ad • http://ga ff erongames.com/networking-for-game-programmers/reliability-and- fl ow-control/

Poor man’s TCP Ordering ✔ Acknowledge Packets ✔ X Resending Packets X Flow Control X Congestion Control

3G UDP ✔ Tested with a few providers in Germany, Switzerland and Netherlands

game barely works on Wi fi : |

game doesn’t work at all on 3G!!! : (

Packet Loss

No synchronization

3

UDP JSON State updates

Full State Full State Full State Full State Send full state

MTU Ethernet 1500 bytes PPPoE 1492 bytes Edge 1440 bytes https://en.wikipedia.org/wiki/Maximum_transmission_unit http://ipixcel.org/EDGE_Capabilities,_Technology,_and_Applications_PDF.pdf

Architecture C1 Server C2 move :up move :down state update state update state update state update game over game over

10 msg/second

100 ms walking speed

Game works on 3G : )

Highscores and Matchmaking are BROKEN! : (

4

Architecture C1 Server C2 move :up move :down state update state update state update state update game over game over

Different Concerns Matchmaking Highscores Game Play Login/Logout User Data Reliable Unreliable

Different Concerns Matchmaking Highscores Game Play Login/Logout User Data HTTP UDP

Server architecture Game Server Lobby Server UDP Service HTTP Service RPC Matchmaking Game Logic Logic User Registry User Registry Database

UDP Binary

Binary protocol 64 bit 32bit 32bit 8bit 8bit Rest User Id SeqNr Ack Bit fi eld Command Payload 144 bits 944 bits 18 bytes 118 bytes

2 Player State update ~ 136 bytes

1.420 KBps ✔ 10 msg/second 56K Modem 7 KBps

Improved Gameplay : )

5

FIFO with timers

Casual Matchmaking 4 Players Match Skill Time

Hierarchical Clustering

Better Matchmaking = 10 =1 =1 1 1 2 10 2 2 3 10 3 3 4 10 4 4 6 10 5 5 10 6 6 10 7 7 Queueing Find Matches Reschedule Start Game

Better Matchmaking : )

Geo Matching

Play Locally : )

Debugging

Terminal Client

Bots

Network Link Conditioner