coherent 400zr osnr link-budget
The 400ZR Reach Math Nobody Shows You

The 400ZR Reach Math Nobody Shows You

Rene Fichtmueller / 2026-05-19 / ~3 min read
MCP Security LLM AI Security Prompt Injection ShieldX MITRE ATLAS Tool Poisoning Claude Open Source
MCP Security: The Attack Surface Nobody Is Auditing

MCP Security: The Attack Surface Nobody Is Auditing

Model Context Protocol gives AI systems tool access. It also creates a new attack surface: tool poisoning, indirect prompt injection, and privilege escalation through tool chaining. Almost nobody is scanning for it.

Rene Fichtmueller / 2026-05-19 / ~2 min read
msa transceivers procurement
MSA-Compliance Is Not Vendor-Compatibility — Procurement Keeps Confusing the Two

MSA-Compliance Is Not Vendor-Compatibility — Procurement Keeps Confusing the Two

The MSA — Multi-Source Agreement — is a document. It is a good document. It defines the mechanical envelope, the pinout, the power envelope, and the management interface for a class of

Rene Fichtmueller / 2026-05-18 / ~3 min read
Personal Mental Health Infrastructure
Rest Is Not Laziness

Rest Is Not Laziness

I used to think stopping meant falling behind. It took me years, a crash, and a lot of uncomfortable honesty to understand that rest is not the opposite of ambition. Sometimes it is the only reason you survive it.

Rene Fichtmueller / 2026-05-16 / ~4 min read
adhd focus personal
ADHD Diary #008: The 47-Tabs Problem

ADHD Diary #008: The 47-Tabs Problem

I closed 47 browser tabs on Tuesday. I know it was 47 because the extension that counts them announced it like a milestone. By Wednesday morning I had 51 open

Rene Fichtmueller / 2026-05-15 / ~3 min read
Open Source Apache 2.0 Licensing Software Engineering Legal Security Patents Developer Tools Community
Why I Licensed Everything Apache 2.0

Why I Licensed Everything Apache 2.0

License choice is a product decision, not just a legal formality. Apache 2.0 over MIT isn't paranoia — it's the patent protection clause, which matters specifically for security software.

Rene Fichtmueller / 2026-05-15 / ~2 min read
coherent long-haul zr transponder
What Coherent ZR Is Eating in Long-Haul (And What It Still Can't Touch)

What Coherent ZR Is Eating in Long-Haul (And What It Still Can't Touch)

Pluggable ZR did to metro DCI what nobody expected at this pace. Between roughly 2022 and 2025, transponder shelves got pulled out of metro builds across most of the hyperscalers,

Rene Fichtmueller / 2026-05-14 / ~3 min read
stack local-first llm infrastructure
The Stack I Actually Ship With in 2026

The Stack I Actually Ship With in 2026

The stack is the side effect, not the project. Two principles drive every decision — keep it local, and move every model to one I trained myself. Everything else is downstream.

Rene Fichtmueller / 2026-05-14 / ~4 min read
dci coherent power lpo
DCI Power Per Bit Has a Floor — And We're Hitting It

DCI Power Per Bit Has a Floor — And We're Hitting It

Every generation of coherent pluggables came with the same chart on the same slide. A clean descending curve, pJ/bit on the Y axis, time on the X axis. Forty

Rene Fichtmueller / 2026-05-13 / ~3 min read
Build in Public Open Source Software Engineering Personal Developer Tools GitHub Transparency Community
Six Weeks of Building in Public: What Actually Happened

Six Weeks of Building in Public: What Actually Happened

I started publishing everything I built six weeks ago. Eight repositories, zero marketing budget, one unexpected outcome: writing about the work changed how I do the work.

Rene Fichtmueller / 2026-05-13 / ~2 min read
// projects & tools
// about the author
Rene Fichtmueller
Social Networker
20+ years building and breaking networks. Optical transport, peering, data center infrastructure. Writing about the things that go wrong at 2AM — and how to prevent them.