Networking Overview

Build Information

Current documentation based on build version: 676042 Last updated: 2025-06-21

System Purpose

The Networking category provides the foundational network communication infrastructure for Don't Starve Together. These systems enable server-client communication, inter-shard coordination, data synchronization, and cluster management essential for multiplayer gameplay across distributed game worlds.

Key Responsibilities

• Server Management: Host configuration, client connections, and session handling
• RPC Communication: Remote procedure calls between clients and server
• Data Synchronization: Network variables for real-time state sharing
• Cluster Coordination: Inter-shard communication and portal connectivity
• Persistence Management: Save data and world generation configuration storage

Architecture Overview

Network Communication Flow

[Client] ←→ [Server/Master Shard] ←→ [Secondary Shards]
    ↓               ↓                       ↓
[User Input] → [RPC Validation] → [State Sync]
    ↓               ↓                       ↓
[UI Updates] ← [NetVars Update] ← [World Events]

Data Synchronization Layers

1. Application Layer: User commands, inventory actions, movement
2. RPC Layer: Validated remote procedure calls and responses
3. NetVars Layer: Automatic state synchronization between instances
4. Cluster Layer: Inter-shard communication and data sharing
5. Persistence Layer: Save data management and world configuration

Recent Changes

Build	Date	Component	Change Type	Description
676042	2025-06-21	Networking	stable	Server management and client connection system
676042	2025-06-21	Network Client RPC	stable	Remote procedure call validation and processing
676042	2025-06-21	Network Variables	stable	Network variable types and synchronization utilities
676042	2025-06-21	Shard Index	stable	Cluster shard data persistence and configuration
676042	2025-06-21	Shard Networking	stable	Inter-shard communication and portal connectivity

Common Integration Patterns

Client-Server Communication

-- Send action from client to server
SendRPCToServer(RPC.LeftClick, action_code, x, z, target)

-- Synchronize health value across all clients
local health_netvar = net_float(inst.GUID, "health", "healthdirty")
health_netvar:set(current_health)

Cross-Shard Coordination

-- Check if other worlds are available
if Shard_IsWorldAvailable("Caves") then
    -- Enable portal connections
    portal.components.worldmigrator:SetEnabled(true)
end

-- Sync boss defeats across shards
Shard_SyncBossDefeated("dragonfly", "Caves")

Server Configuration

-- Configure dedicated server
local server_data = GetDefaultServerData()
server_data.name = "My DST Server"
server_data.max_players = 6

-- Save shard configuration
local shard_index = ShardIndex()
shard_index:SetServerShardData(world_options, server_data)

Core Modules

Module	Status	Purpose
Networking	stable	Core server management, client connections, and multiplayer features
Network Client RPC	stable	Remote procedure call system for client-server communication
Network Variables	stable	Network variable types and utilities for synchronized client-server communication
Shard Networking	stable	Inter-shard communication and synchronization system for cluster management
Shard Index	stable	Cluster shard management system for server data persistence and configuration

System Interactions

Client Request Processing

1. Input Capture: Client captures user input (mouse clicks, keyboard)
2. RPC Generation: Client generates appropriate RPC with validation
3. Server Processing: Server validates and processes RPC request
4. State Update: Server updates game state and triggers NetVar changes
5. Client Sync: NetVars automatically sync updated state to all clients

Cross-Shard Synchronization

1. Event Detection: Shard detects important game events (boss defeats, portal use)
2. RPC Transmission: Shard sends event data to master shard via SHARD_RPC
3. Master Processing: Master shard validates and broadcasts to relevant shards
4. State Application: Each shard applies synchronized state changes
5. Confirmation: Acknowledgment ensures consistency across cluster

Data Persistence Flow

1. Configuration Setup: ShardIndex manages world generation and server settings
2. Session Management: Active session data tracked with unique identifiers
3. Periodic Saves: World state serialized and stored persistently
4. Migration Support: Save data enables seamless shard switching
5. Recovery System: Rollback capabilities for save corruption handling

Network Variable Efficiency

Type Selection Guidelines

• net_bool: Single-bit flags and boolean states
• net_byte/net_shortint: Small counters and enumerated values
• net_float: Health percentages and continuous values
• net_string: Player names and dynamic text
• net_entity: Object references and relationships

Performance Considerations

• Use smallest appropriate netvar type to minimize bandwidth
• Avoid frequent updates to expensive array netvars
• Leverage set_local() for client-side predictions
• Group related state changes to reduce network traffic

Security and Validation

RPC Protection

• Parameter type validation using check* functions
• Position validation prevents teleportation exploits
• Rate limiting blocks RPC flooding attacks
• Server authority maintains game state integrity

Data Integrity

• Session identifiers prevent save data corruption
• Version management handles save format upgrades
• Checksum validation ensures data consistency
• Rollback systems recover from corruption events

Best Practices

Network Design

1. Minimize Bandwidth: Choose optimal netvar types and avoid unnecessary updates
2. Validate Everything: Use provided validation functions for all RPC parameters
3. Handle Failures: Implement proper error handling for network operations
4. Maintain Authority: Server always has final authority over game state
5. Plan for Scale: Design systems to handle maximum player capacity

Cluster Management

1. Graceful Degradation: Handle shard disconnections without breaking gameplay
2. Consistent State: Ensure critical data synchronized across all shards
3. Performance Monitoring: Track network performance and connection quality
4. Recovery Procedures: Implement automatic recovery from network failures
5. Resource Management: Monitor and limit resource usage across cluster

Troubleshooting Guidelines

Common Network Issues

• RPC Validation Failures: Check parameter types and value ranges
• NetVar Synchronization: Ensure identical declarations on server and clients
• Shard Communication: Verify portal bindings and world availability
• Save Corruption: Use rollback system and verify session identifiers
• Performance Degradation: Monitor bandwidth usage and optimize netvar updates

Debugging Tools

• RPC logging for validation failure analysis
• NetVar dirty event tracking for sync issues
• Shard connection monitoring for cluster health
• Save data integrity verification utilities
• Network performance profiling capabilities

Related Systems

• Chat Commands: Player communication and admin command systems
• Multiplayer: Multiplayer-specific UI and content delivery systems
• Components: Game object components with network integration
• World Systems: World generation and entity management with cluster support