Notes

What I have actually seen work, and the conditions under which it stops working. Written between projects; corrections are published, not quietly edited.

2026-11-01 · 7 min
What a CCIE Number Does Not Tell You
What the CCIE lab measures, what it misses, and how I judge network engineering competence in interviews and on the job.
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2026-11-01 · 7 min
Reading a BGP Looking Glass When a Prefix Disappears
A prefix vanishes, the looking glass shows nothing, and everyone assumes BGP is down. A working order for reading state codes, paths and policy.
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2026-11-01 · 7 min
MPLS vs SRv6 for Operators: What Actually Changes
MPLS and SRv6 compared by what changes in the data plane, what the migration really costs, and the runbooks a team has to rebuild.
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2026-11-01 · 7 min
Lossless Ethernet for AI Clusters: PFC, ECN and the Failure Modes That Bite
Why PFC, ECN and buffer sizing fail together in AI Ethernet fabrics, and the stall patterns that never show up as a packet drop.
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2026-11-01 · 6 min
Why Spine-Leaf Broke the Three-Tier Model
Spine-leaf did not just replace a topology. It moved the L2/L3 boundary, split operations into underlay and overlay, and changed what you debug.
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2026-11-01 · 7 min
Five SD-WAN Migration Failure Modes in the Real Network
Five places SD-WAN migrations break in production: centralised policy, asymmetric paths, app classification, DNS, and a rollback nobody tested.
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