HERMES
Hardened Edge Relay & Machine-intelligent Encrypted Speech
HERMES is the unified communications platform for GVA military vehicle systems. It delivers secure encrypted voice, rich media messaging, and AI-powered human-to-machine interfacing across tactical networks — from high-bandwidth LAN to degraded RF links.
Designed for DEF STAN 23-009 compliance, HERMES provides everything from crew intercom to vehicle-to-command post communications, all protected by military-grade encryption.
Core Capabilities
Encrypted Voice
End-to-end encrypted voice using SRTP (AES-256-CM) with military-grade codecs including MELPe and STANAG 4591. Supports crew intercom, vehicle-to-vehicle, and vehicle-to-command post.
Rich Media Delivery
Encrypted text messaging, file transfer, presence indicators, group notifications, and searchable call logs — all over the same secure SIP infrastructure as voice.
System Architecture
SIP Registrar/Proxy] AGT[VoIP Agent
AI Assistant] MCP[MCP Tool Server
Vehicle Tools] end subgraph "Clients" CLI1[VoIP Client 1
Crew Station] CLI2[VoIP Client 2
Commander] CLI3[VoIP Client 3
Driver] end subgraph "External Networks" EXT[External SIP
Gateway/Trunk] AI[Ollama LLM
Local Inference] end CLI1 <-->|SIP/RTP| SRV CLI2 <-->|SIP/RTP| SRV CLI3 <-->|SIP/RTP| SRV AGT <-->|SIP/RTP| SRV SRV <-->|SIP Trunk| EXT AGT <-->|HTTP| AI AGT <-->|MCP| MCP style SRV fill:#4CAF50 style AGT fill:#9C27B0 style MCP fill:#FF9800 style CLI1 fill:#2196F3 style CLI2 fill:#2196F3 style CLI3 fill:#2196F3
Components
VoIP Server
The VoIP Server acts as a SIP registrar and proxy, managing call routing between clients within the vehicle network and to external networks.
- SIP user registration and authentication
- Call routing and proxying
- CDR (Call Detail Records) logging
- DSCP EF (Expedited Forwarding) QoS marking
- Military codec support (MELPe, STANAG 4591)
- Multiple simultaneous call handling
- Call forwarding and forking
VoIP Client
Available as both a standalone desktop application and a GVA External App integrated into the VivoeX HMI COM screen (F7).
- SIP registration and encrypted calling
- Multiple codec support (G.711, G.729, MELPe, Opus)
- SRTP encryption (RFC 3711)
- Address book management
- Headless mode for intercom/relay
- Auto-answer with WAV playback
- DDS registration via GVA Registry Service
VoIP Agent (AI Assistant)
An AI-powered voice assistant providing the human-to-machine interface. Operates entirely offline with no cloud connectivity required.
- Ollama/Gemma LLM integration (local inference)
- Piper TTS (offline text-to-speech)
- Vosk STT (offline speech recognition)
- MCP (Model Context Protocol) tool support
- Military coordinate tools (MGRS, bearing, distance)
- Multi-turn conversational context
- Standalone mode (local mic/speaker)
MCP Tool Server
Exposes vehicle system tools to the AI agent via the Model Context Protocol, enabling natural language access to platform capabilities.
- MGRS coordinate conversion
- Bearing and distance calculations
- Vehicle system status queries
- Date-Time Group (DTG) formatting
- Extensible tool plugin architecture
- Custom MCP server chaining
Audio Codecs
| Codec | Bitrate | Sample Rate | Description |
|---|---|---|---|
| G.711 μ-law | 64 kbps | 8 kHz | Standard telephony, highest quality |
| G.711 A-law | 64 kbps | 8 kHz | European telephony standard |
| G.729 | 8 kbps | 8 kHz | Low bandwidth, good quality |
| MELPe | 2.4 kbps | 8 kHz | Military standard (MIL-STD-3005) |
| STANAG 4591 | 1.2–2.4 kbps | 8 kHz | NATO interoperability (TSVCIS) |
| Opus | 6–510 kbps | 48 kHz | Modern, adaptive bitrate |
Security & Standards
SRTP Encryption
All voice communications are encrypted using SRTP (Secure Real-time Transport Protocol) per RFC 3711 with AES-256-CM-HMAC-SHA1-80 cipher suite. Key exchange is performed via SDP during call setup.
Encryption is always enabled and cannot be disabled — suitable for OFFICIAL-SENSITIVE classification.
Network QoS
VoIP traffic is marked with DSCP EF (Expedited Forwarding, 46) for priority handling on managed networks. This ensures voice packets receive preferential treatment over data traffic.
Integrates with DiffServ-aware tactical network equipment and military-grade switches.
Standards Compliance
SIP Signalling
| RFC | Title | Usage |
|---|---|---|
| RFC 3261 | SIP: Session Initiation Protocol | Core call signalling |
| RFC 3264 | Offer/Answer Model with SDP | Codec negotiation |
| RFC 3265 | SIP-Specific Event Notification | Presence and subscriptions |
| RFC 3428 | SIP Extension for Instant Messaging | Text messaging (MESSAGE) |
| RFC 3515 | SIP REFER Method | Call transfer |
Media & Transport
| RFC | Title | Usage |
|---|---|---|
| RFC 3550 | RTP: Real-Time Transport Protocol | Audio media delivery |
| RFC 3711 | SRTP: Secure Real-time Transport Protocol | Media encryption (AES-256-CM) |
| RFC 4568 | SDP Security Descriptions | SRTP key exchange via SDP |
| RFC 4733 | DTMF Relay via RTP | In-band DTMF tones |
Military Standards
| Standard | Description |
|---|---|
| MIL-STD-3005 | MELPe voice codec (2.4 kbps tactical voice) |
| STANAG 4591 | NATO narrowband & wideband voice coding |
| DEF STAN 23-009 | UK GVA Land Data Model (DDS integration) |
| RFC 2474 / RFC 3246 | DiffServ QoS (DSCP EF marking) |
Platform Support
| Platform | Architecture | Status |
|---|---|---|
| Ubuntu 22.04 LTS | x86_64 (AMD64) | ✅ Full Support |
| Ubuntu 24.04 LTS | x86_64 (AMD64) | ✅ Full Support |
| Embedded Linux | ARM64 (AArch64) | ✅ Full Support |
| Real-time OS | x86_64 / ARM64 | ✅ Available |
Dependencies: Qt 6.2+, OpenSSL 3.0, CMake 3.20+, Ollama (for AI agent), Vosk, Piper
Key Differentiators
Fully Offline AI
LLM inference, speech recognition, and speech synthesis all execute locally on the vehicle compute platform. No cloud. No latency. No data exfiltration risk.
GVA Integrated
Native integration with VivoeX HMI, DDS Registry Service, and the full GVA software stack. Registered as a communication service via DEF STAN 23-009.
Get Started with HERMES
HERMES is included as part of the VivoeX SDK and is available to licensed customers. Contact us for a demonstration of secure military communications in action.