How to use this course¶
Suggested learning path¶
You will be the point of contact for the platform, so the course is built as a path from "what is TRex at all" to "I can explain every packet and every number on the dashboard". A realistic pace is one chapter per sitting.
- Week 1 - foundations (Part I). Chapters 1-5 are the core: measurement terms, what TRex is, how the TRex server works internally, how stateless streams are built and how TRex counts packets and measures latency. Chapters 6-9 add the emulated hosts (EMU), stateful testing (ASTF), InfluxDB and Grafana.
- Week 2 - the LVR platform (Part II). Chapters 10-19 apply the foundations to the LVR fabric: why the TX switches use QinQ, how an attachment point works, what each traffic class measures, why the monitoring profile looks the way it does, how the server is built and how data flows into Grafana.
- Week 3 - operation (Part III). Chapters 20-25: daily operation, step-by-step scenarios, safety rules for a production network and troubleshooting.
- Keep the appendices at hand - cheat sheets for the TRex console, the Python API, Comware verification commands and Flux queries; the reference configuration; the glossary.
Every chapter starts with learning objectives and ends with Key takeaways and Check your understanding questions. The answers are collapsed - try to answer first, then click to compare.
Conventions¶
Boxes¶
Why is it done this way?
Design rationale - the reason behind a mechanism or a decision. These boxes are the heart of the course: if you can explain the why, you can support the platform.
In the LVR platform
How a generic TRex/Grafana concept is applied in the LVR setup (device names, VLANs, ports, addresses).
Production impact
Anything that can affect production traffic, and how to avoid it. Read these boxes twice.
Open decision
A design question that is not yet decided. The box shows the options and their consequences.
Tip
Practical hints for daily work.
Status badges¶
| Badge | Meaning |
|---|---|
| verified | Command or fact verified for the exact platform and release (source given) |
| confirm on device | Plausible and consistent with the documentation, but must be confirmed live or on the bench before use |
| decision | Depends on an open design decision |
| from TRex docs | Output or example copied from the official TRex documentation |
| illustrative values | Example values made up for teaching - real values will differ |
About example output
There is no TRex lab yet, so this course never shows invented output as if it were real. Outputs are either copied from the official documentation, taken from the LVR diagnostic files of February 2025, or clearly marked as illustrative.
Names used throughout¶
| Term | Meaning |
|---|---|
| RZK / RZC | Data centres Kalk and Chorweiler |
| TX switch | Dedicated TRex distribution switch, one per DC: sw-rzk-TX1, sw-rzc-TX1 |
| AP | Attachment point - a 10G link from a TX switch into a Leaf or Border Leaf, e.g. K-L11, C-BL |
| S-VLAN / C-VLAN | Outer / inner 802.1Q tag. On the TX switches the S-VLAN selects the AP, the C-VLAN is the production VLAN |
| trex-mon / trex-lab | The two TRex instances on the server: permanent monitoring / on-demand tests |
| Stream | One unidirectional TRex packet flow with its own statistics (identified by a pg_id) |
| Latency stream / flow-stat stream | Stream that measures latency + loss / stream that measures loss only |
| Class | Traffic class: L2, L3-BL, L3-DCFW, L3-ENTFW, DSCP, LAB |
Animations and videos¶
Animated diagrams have a control bar: Play/Pause, Prev/Next step, Restart and Speed. Each animation is also available as an MP4 video (link in the control bar, and all videos on the page Animation videos). If you print a page from the browser, its animations appear as storyboards - one frame per step with its caption.
Try it - this is the animation from chapter 12 that shows what the TX switch does to a monitoring frame:
Building the site¶
The course is written in Markdown (folder docs/) and built with MkDocs Material.
cd artifacts/trex-training
./build.sh # HTML site in site/
./build.sh --serve # live preview on http://127.0.0.1:8000 while editing
./build.sh --videos # also re-render the MP4 videos from the animation specs
See README.md in the course folder for details on editing text, diagrams and animations.