This document provides an overview of networking concepts for game programming, including: - Latency vs lag and techniques for fighting lag like client-side prediction and interpolation. - Network stack components like sockets, TCP vs UDP, and IP addressing. - Procedures for programming sockets in games including initialization, creating sockets, connecting, sending/receiving data, and cleanup. - Other topics covered include peer-to-peer vs client-server architectures, byte ordering, and demonstrations of networking code in NodeJS, C++, and websockets.

1. Game Network
Programming
@CoreyClarkPhD
@GameTheoryLabs

2. !
What I Did?

3. What I Do Now
Crowd
Sourced
Games
Distributed
ComputingMMOs
FoldIt
Crowd
Process
GTL

4. Determinism & Lock Step
Authoritative Server
Mid-Game Join
Floating point

5. Latency vs Lag

6. Fight Lag
! What is the Cause?
! Slower But Consistent Frame Rate
! Animations
! Client Side Prediction
! Learning Algorithms
! Markov Models
! Artificial Neural Networks

7. Client Side Prediction
Linear Interpolation
Jitter / Wobble

8. The Internets …

9. Peer To Peer (P2P)

10. Client / Server

11. Mesh

12. Network Stack

13. Sockets
! Extends Network Layer (Host to Host)
! End – to – End (App to App)
! APIs: WinSock & Berkley (BSD)

14. TCP vs UDP
TCP
! Connection Based
! Delivery Guarantee
! Order Guarantee
! Flow Control
! Duplicates Deleted
UDP
! Connectionless
! No Delivery Guarantee
! No Order Guarantee
! No Flow Control
! Duplicates

15. TCP/IP Network
Host
App
Socket
TCP
IP
Channel Channel
Host
App
Socket
TCP
IP
Ethernet,
WiFi,
Bluetooth

16. Addresses
External Address
Internal Address
MAC Address
ISP
Geo Referenced
Router
Hardware
IEEE Regulated

17. Ports
! Communication End
Point
! Port Forwarding
! Internal Static IP
! Stay above 1024
! Common Ports
! 20: FTP
! 80: HTTP
! 443: HTTPS
! Registered Ports
! 7778: Unreal
! 26000: Quake
! 27010: Half-Life
! 27960: Quake III

18. Programming Sockets
! Blocking
! Non-Blocking
! Overlapped I/O
! Event Handle
! Completion Port

19. WinSock Procedure
Client
! WinSock Init
! Create Socket
! Connect
! Send/Recv
! Close Socket
! WinSock Clean Up
Server
! WinSock Init
! Create Socket
! Bind
! Listen
! Accept (New Socket)
! Send /Recv
! Close Socket
! WinSock Clean Up

20. TCP Procedure
Create
Socket
Bind Listen Accept
Create
Socket
Connect
Send
Recv
Send
Recv

21. Byte Order
Endianness
! Big Endian
! MSB in Smallest Addr
! Intel
! Little Endian
! LSB in Smallest Addr
! Motorola
Host vs Network
! Host Byte Order (Intel
(Big-Endian)
! Network Byte Order (Big-
Endian)
! htons, htonl
! ntohs, ntohl
SockAddr.sin_port = htons(nPort);

22. Startup & Cleanup
WSAStartup( MAKEWORD(2,2), &WSADATA)
WSACleanup()

23. Create Socket
socket(AF_INET,
SOCK_STREAM,
IPPROTO_TCP);
socket(AF_INET,
SOCK_DGRAM,
IPPROTO_UDP);

24. Connect
connect(SOCKET tcp,
const struct sockaddr* SockAddr,
sizeof(SockAddr))

25. Send
int send( SOCKET s,
const char *buf,
int len,
int flags);

26. Demo
NodeJS
Server
Web Viewer
C++ TCP Client WebSocket Client

27. Help Me Out
gametheorylabs.com/smuGo To:
Pick Color
Set Color

28. Questions?