Deterix: Deterministic Network Emulator with Microsecond Timing Precision

Deterix is a lightweight network emulator written in Rust for building distributed applications that require precise timing control. It provides time-slotted communication with <1µs jitter on COTS hardware running Linux with PREEMPT_RT patch.

Features

• Time-slotted communication (TDMA)
• Microsecond timing precision (<1µs jitter)
• No GC interruptions
• Zero-copy packet handling
• Distributed architecture

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

1. Initialization Phase

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

2. 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

1. Slot Assignment

   • Deterministic sender/receiver pairs per slot
   • Scheduled transmission windows
   • Guard bands prevent overlap

2. 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