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unitree-g1/context/networking-comms.md

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id title status source_sections related_topics key_equations key_terms images examples open_questions
networking-comms Networking & Communications established reference/sources/official-quick-start.md, reference/sources/official-developer-guide.md [sdk-programming ros2-integration deployment-operations] [] [dds cyclone_dds domain_id dual_computer_architecture locomotion_computer development_computer] [] [] [WiFi 6 range and reliability in field conditions DDS QoS profile details and tuning WiFi AP exact SSID format and default password USB port availability and specs]

Networking & Communications

Network architecture, connectivity, remote access, and communication protocols.

1. Network Architecture

The G1 uses a fixed internal subnet with pre-assigned IP addresses: [T0 — Developer Guide]

                    192.168.123.0/24
                          │
    ┌─────────────────────┼──────────────────────┐
    │                     │                      │
Locomotion          Development              LiDAR
Computer            Computer              (Livox MID360)
192.168.123.161    192.168.123.164        192.168.123.20
(Proprietary)      (Jetson Orin NX)       (Ethernet)
    │                     │
    └──── CycloneDDS ─────┘
          (internal)

IP Address Map

Device IP Address Access Level
Locomotion Computer 192.168.123.161 Not user-accessible
Development Computer 192.168.123.164 User-accessible (SSH)
Livox MID360 LiDAR 192.168.123.20 Ethernet, driver required
External dev machine 192.168.123.x Via WiFi or Ethernet

2. Connectivity Options

Interface Specification Purpose Tier
WiFi WiFi 6 (802.11ax) Wireless development, remote control T0
Bluetooth Bluetooth 5.2 Peripheral connectivity T0
Ethernet Wired connection LiDAR, high-bandwidth data T0
USB Available on dev computer Camera (D435i), peripherals T1

3. DDS Configuration

The entire communication stack is built on DDS (Data Distribution Service): [T0]

Property Value
Implementation CycloneDDS
Version 0.10.2 (exact match required)
Protocol RTPS (Real-Time Publish-Subscribe)
Communication latency 2 ms
Control loop rate 500 Hz

Domain ID

The DDS domain ID controls which "network" of DDS participants can communicate:

  • Real robot: Use the robot's network interface (e.g., enp2s0, wlan0)
  • Simulation: Use domain ID to separate simulated robot traffic from real
  • Switch: Changing from sim to real only requires switching the network config (domain ID + interface)

Topic Architecture

All robot communication uses DDS topics (see sdk-programming for full topic list):

Publishers (user) ──→ rt/lowcmd    ──→ Locomotion Computer (motor commands)
Subscribers (user) ←── rt/lowstate ←── Locomotion Computer (robot state)
Publishers (user) ──→ rt/dex3/*/cmd ──→ Hand Controller (hand commands)
Subscribers (user) ←── rt/dex3/*/state ←── Hand Controller (hand state)

4. Remote Access

  • SSH: Connect to development computer: ssh unitree@192.168.123.164 (password: 123) [T1 — Weston Robot guide]
  • Data streaming: DDS topics accessible from any machine on the 192.168.123.0/24 subnet [T0]
  • Camera streaming: D435i frames accessible via RealSense SDK on dev computer [T1]
  • LiDAR data: Point cloud data from Livox MID360 at 192.168.123.20 [T0]

Connecting an External Development Machine

  1. Connect to robot's WiFi network or plug into Ethernet
  2. Configure machine's IP to 192.168.123.x (avoid .161, .164, .20)
  3. Install CycloneDDS 0.10.2 and unitree_sdk2
  4. Subscribe to rt/lowstate to verify connectivity

5. Latency Considerations

Path Latency Notes
DDS internal (dev ↔ locomotion) ~2 ms CycloneDDS over internal net
WiFi (external ↔ dev computer) Variable Depends on WiFi conditions
Control loop 2 ms (500 Hz) Locomotion computer rate
LiDAR point cloud — Depends on scan rate

Critical: For real-time control, use wired Ethernet or develop directly on the Jetson to minimize latency. WiFi adds variable latency that can affect control stability. [T2]

Key Relationships