Study and prototyping the advantages of TSN extensions on Linux for time based traffic scheduling in the context of the M1 LCS deterministic network

Background:


The ELT M1 LCS operation relies on a shared synchronous heart beat in the form of a multicast IP packet. These packets trigger the actions, measurements and responses from the many field electronics devices.
The Time Sensitive Networking (TSN) extensions allow real-time capable and deterministic communication via conventional Ethernet. Standard Linux provides features that allows the implementation of TSN, in particular time (TAI) based scheduling (i.e. ETF qdisc policy) along with SO_TXTIME socket options.

 

Objectives:

  1. Study the state of the art and applicability of TSN on off-the-shelf hardware (network interfaces and switches) and standard ELT OS (Fedora + PREEMPT_RT).
  2. Evaluate and benchmark sending a periodic packet (500Hz) using ETF qdisc policy + SO_TXTIME with and without hardware scheduling time offload (with network card of type I210 and standard ELT), and compare also with current busy loop (i.e. read time and send until the deadline is reached).
  3. Discussion of trade-offs (advantages/disadvantages), constrains, compatibility/maintenance issues (i.e. is ETF policy maintained? is tx time hardware offload provided anywhere else?), applicability to the rest of the traffic (not SYNC), etc.
  4. Conclusions and future work.

 

References:
. TSN and Linux: linutronix.de/PDF/DS_2022_TSN_Linux_V1.0_E_A4.pdf

 

Supervisors:  N. Kornweibel and J. Argomedo