DirectPlay8

1
DirectPlay8

• Kevin Gee
• Windows Gaming Entertainment
• Microsoft Corporation

2
Agenda

• Introduction to DirectPlay
• Features
• Services
• Protocol
• Whats New in DirectPlay for DirectX 9

3
DirectPlay8 ConfigurationsGaming Topologies

• Client-Server
• Dungeon Siege (Gas Powered Games)
• Giants (Planet Moon Studios)
• JumpGate (NetDevil)
• Peer-peer
• Sacrifice (Shiny Entertainment)
• MechWarrior4 (Microsoft)
• GameVoice (Microsoft)

4
DirectPlay8 Client-Server

• Clients do not know of other clients
• All sends routed via the server
• Server must be capable of handling several
  clients
• Suitable for large games with many players
• Massively Multiplayer Games

5
DirectPlay8 Peer-Peer

• Players are connected to all other players
• Sends may targeted at other players directly
• Host migration (Managed for you)
• Suitable for small(er) numbers of players

6
DirectPlay8 API

• Easy to use and understand
• Deterministic behavior
• Logical message order
• Matched messages
• Create \ Destroy matching handled automatically
• Groups
• Send to Multiple targets more efficiently

7
DirectPlay8 API

• Powerful
• Asynchronous operations
• Overlapped I/O
• NT I/O Completion Ports
• Application payloads when connecting and
  enumerating sessions
• Player context values

8
DirectPlay8 API

• Flexible
• Select ports
• Multiple service providers / adapters / ports
• Asynchronous or synchronous operations
• Send parameters
• Reject connections
• Ignore enumerations
• Scalability parameters
• Push model

9
Push Model

• Messages are pushed to the application via
  call-back function
• Thread pool
• Multithreaded
• Scalable
• A pull (polling) model can be implemented if
  required

10
DirectPlay8 Architecture
Application
API Calls
Call-backs
DirectPlay8
API / Core
Transport Protocol
IPX SP
Modem SP
Serial SP
IPv6 SP
IPv4 SP
11
DirectPlay8 Core

• Implements API
• Performs callbacks to applications message
  handler function
• Performs name table management
• Co-ordinates service provider usage
• Provides integration with DirectPlay8Voice and
  DirectPlay8Lobby

12
DirectPlay8 CoreHost Migration

• Host migration for peer-peer sessions
• Deterministic host election based on connect
  order
• Guaranteed transactions
• No session fragmentation

13
DirectPlay8 Protocol

• Service provider agnostic
• Guaranteed / non-guaranteed and sequential /
  non-sequential messages
• Based on UDP when over IP
• Automatic send throttling
• Send timeouts
• Low overhead

14
DirectPlay8 Service Providers

• Several provided
• IPv4
• IPX
• Modem
• Serial
• New
• IPv6
• Bluetooth (Pocket PC)

15
DirectPlay8 Reliability

• DirectPlay8 is a complete rewrite
• Robust error recovery
• Edge conditions
• Deterministic behavior
• Connecting, disconnecting, host migrating
• Well Tested

16
DirectPlay8 Scalability

• Written to scale
• Multithreaded to support multiple processors
• Written to be fast
• No buffer copies in send path
• No context switches in send or receive path
• Tested with several thousand clients
• Optimal and suboptimal conditions

17
Whats New in DirectPlay ?DirectPlay for DirectX
9

• DirectX 9 keeps the DirectPlay 8 Interfaces
• NAT/Firewall traversal support
• Most NATs and firewalls for client-server
• Windows ME and XP for peer-peer
• UPNP H/W NATs

18
Whats New in DirectPlay ?

• Packet Coalescence
• On Resends
• Without waiting around
• Packet Signing
• Prevents Spoofing (2 versions)
• Fast Very efficient
• Full More secure
• Generally Improved Performance

19
Whats New in DirectPlay ?

• Exposed Thread Pool Interface
• You decide how many threads Direct Play will use
• Allows thread priority modifications
• Thread start/shutdown notification
• Create a data pool for each thread to work with
• OR Even
• Zero thread DoWork() mode supported

20
Whats New in DirectPlay ?

• Pocket PC Support
• No DirectPlay Voice support
• Bluetooth support
• IPv6 added to Direct Play 9
• Determines availability
• Assists with NAT traversal
• Falls back to IPv4
• Direct Play Protocol Tuning Enhancements
• Tunable Parameters
• Packet Throttling
• Automatic send throttling

21
Why use DirectPlay8 ?

• Great platform for networked games
• Robust
• Scalable
• DirectPlay makes networking easier
• Service provider agnostic
• Services like voice and lobby
• ICS ICF Friendly
• Handles NAT for you
• Leverage our work and resources
• Save time and money !

22
Call to Action!

• Get on the DirectX 9 Beta
• Beta 2 Shipped!
• Use the SDK Tutorials to learn from
• Look out for the DirectPlayX library
• Best Practice Whitepaper and lib
• Client side serialization case study
• Provide Feedback
• Future improvements