Deterix: Deterministic Network Emulator with Microsecond Timing Precision

Deterix is a lightweight communication framework designed specifically for modular digital twins requiring deterministic data exchange. Built on PREEMPT_RT Linux, it achieves microsecond-precision timing on commodity hardware through pure software implementation, enabling reliable real-time communication between digital twin components without requiring specialized hardware. The framework leverages standard Commercial Off-The-Shelf (COTS) computers and regular network infrastructure, making it an accessible solution for distributed digital twin deployments.

Features

Time-slotted communication (TDMA)
Guaranteed message delivery windows
Microsecond timing precision of slot ticker
No GC interruptions
Zero-copy packet handling
Distributed architecture
Runs on any modern COTS hardware

Network Architecture

Overview

The network operates on a Time Division Multiple Access (TDMA) protocol with Node 0 serving as the network orchestrator. Key architectural features include:

Distributed time synchronization with <1µs precision
Deterministic slot-based communication
Dynamic network formation and management

Slot Structure

|<------------------------ SLOTFRAME (8 slots) ------------------------>|
+--------+--------+--------+--------+--------+--------+--------+--------+
| Slot 0 | Slot 1 | Slot 2 | Slot 3 | Slot 4 | Slot 5 | Slot 6 | Slot 7 |
| IDLE   | DEDIC  | DEDIC  | DEDIC  | SHARED | SHARED | SHARED | SHARED |
| -/-    | 1/2    | 2/3    | 3/1    | */0    | */0    | 0/*    | */0    |
+--------+--------+--------+--------+--------+--------+--------+--------+


|<----------------------------- Single Slot ----------------------------->|
+-------+-----------------------------------+---------------------+-------+
| CLEAR |               TX/RX               |         ACK         | GUARD |
|  10%  |                50%                |         30%         |  10%  |
+-------+-----------------------------------+---------------------+-------+

Example transmission-slot chart showing two nodes join and synchronize with orchestrator and send 10 data packets in their dedicate slots.

Time Synchronization

Node 0 (Orchestrator)
- Provides network-wide time reference using system clock
- Manages slot timing and synchronization
- Broadcasts periodic sync messages
Other Nodes
- Maintain synchronized local clocks
- Update timing based on sync messages
- Calculate slot boundaries locally

Network Operations

Network Formation

Initialization Phase
- Node 0 starts as orchestrator
- Dedicated join slots are reserved in each slotframe
- New nodes begin in unsynchronized state

Join Process

New Node                  Node 0 (Orchestrator)
   |                              |
   |------ Join Request --------->| (in shared slot)
   |                              | - Records node and add schedule
   |                              | - Prepares timing info
   |<----- Join Response ---------|
   |                              |
   |- Synchronize local clock     |
   |- Start normal operation      |

Communication Protocol

Slot Assignment
- Deterministic sender/receiver pairs per slot
- Scheduled transmission windows
- Guard bands prevent overlap
Transmission Process
- Reliable delivery with ACK mechanism
- Automatic retransmission
- Sequence number tracking

Implementation Details

Core Components
- TX/RX Queue Management
- Slot Ticker System
- Zero-copy Packet Pool
- RT Thread Scheduling
Performance Features
- Thread affinity optimization
- RT scheduler prioritization
- Efficient buffer management
- Microsecond-precision timing

LICENSE

GPL-3.0

AmyangXYZ/deterix