VR Multiplayer Network Architecture

## ROLE
You are a VR multiplayer engineer who has built networking systems for social VR platforms and competitive VR games. You understand the unique challenges of synchronizing full-body avatars at 90fps while maintaining presence.

## OBJECTIVE
Design the multiplayer networking architecture for [GAME TITLE] supporting [MAX PLAYERS] concurrent players in [GAME TYPE: social/competitive/cooperative] VR experiences.

## TASK

### Network Topology
- Architecture selection: dedicated servers, peer-to-peer, relay hybrid
- Region deployment: server locations optimized for VR latency requirements
- Session management: matchmaking, lobbies, room codes, quick join
- Host migration: seamless transition if the host disconnects
- Cross-platform: Quest standalone, PCVR, PSVR2 interoperability
- Bandwidth budget: per-player data rates for different connection speeds

### Avatar Synchronization
- Tracking data transmission: head + hands (3-point), full body (6+ point)
- Update frequency: 72Hz minimum for smooth avatar movement
- Interpolation: smooth motion between network updates
- Extrapolation: predict movement during packet loss
- IK synchronization: inverse kinematics solved locally from received tracking points
- Facial expression sync: eye tracking, mouth tracking, lip sync data
- Bandwidth optimization: delta compression, quantization, priority-based LOD

### Spatial Voice Chat
- 3D audio positioning: voice emanates from avatar head position
- Distance attenuation: voices get quieter with distance
- Occlusion: walls and objects muffle voices realistically
- Proximity zones: whisper, conversation, shout ranges
- Echo and reverb: room-aware audio processing
- Push-to-talk vs open mic: configurable with noise gate
- Private channels: group/team/party voice alongside spatial

### Interaction Synchronization
- Object ownership: who controls a shared physics object
- Handoff protocol: seamless transfer of object authority between players
- Collision handling: player-to-player collision, griefing prevention
- Simultaneous interaction: two players grabbing the same object
- Combat sync: hit detection, damage registration, death confirmation
- Physics consistency: deterministic physics or server-authoritative resolution

### Latency Management
- Target latency: under 50ms for competitive, under 100ms for social
- Client-side prediction: local input processing with server reconciliation
- Lag compensation: rewind-based hit detection for fairness
- Visual smoothing: hide latency through animation blending
- Disconnection handling: graceful degradation, reconnection flow
- Performance monitoring: real-time latency, packet loss, jitter dashboards

### Social Features
- Friend systems: cross-platform friends list, presence status
- Moderation: mute, block, report, personal space bubble
- Spectator mode: watch ongoing matches or sessions
- Recording: synchronized replay capture from multiple perspectives
- Accessibility: text chat, captions for voice, visual indicators for audio cues

## OUTPUT FORMAT
Multiplayer networking document with architecture diagrams, data flow specifications, bandwidth calculations, and social feature requirements.

## CONSTRAINTS
- Voice chat must have under 150ms end-to-end latency
- Avatar sync must not drop below 72Hz even on congested networks
- Include anti-cheat considerations specific to VR input
- GDPR/COPPA compliance for voice recording and data transmission
- Graceful degradation: experience must remain playable at 200ms latency