LATEST
coherent
400zr
osnr
link-budget
Open any 400ZR datasheet and you'll find a reach number. 120 km. Sometimes 80 km. Sometimes 140 km on the more aggressive specs. That number is a clean-link ceiling. It is not the distance you should be designing
Rene Fichtmueller
/
2026-05-19
/
~3 min read
MCP
Security
LLM
AI Security
Prompt Injection
ShieldX
MITRE ATLAS
Tool Poisoning
Claude
Open Source
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
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
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~3 min read
Personal
Mental Health
Infrastructure
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
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2026-05-16
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~4 min read
adhd
focus
personal
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
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2026-05-15
/
~3 min read
Open Source
Apache 2.0
Licensing
Software Engineering
Legal
Security
Patents
Developer Tools
Community
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
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2026-05-15
/
~2 min read
coherent
long-haul
zr
transponder
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
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2026-05-14
/
~3 min read
stack
local-first
llm
infrastructure
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
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2026-05-14
/
~4 min read
dci
coherent
power
lpo
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
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2026-05-13
/
~3 min read
Build in Public
Open Source
Software Engineering
Personal
Developer Tools
GitHub
Transparency
Community
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
// 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.