A router datasheet lists 8 queues per port, strict priority, WRED and hierarchical shaping. The design document marks voice as EF and puts it in the priority queue. Both …
Alexander Zemskov
4 min read
A vendor slide says "failover under 50 ms". The figure is usually taken on an idle box: one flow, two links, default timers. In production the same failure hits a router …
Alexander Zemskov
4 min read
A tender for an aggregation switch usually has one line about performance: "wire speed on all ports". Every vendor on the shortlist ticks it, and every tick is honest at …
Alexander Zemskov
4 min read
A data centre fabric is accepted in 2 steps. Step 1: the integrator shows that two hosts on different leaves can ping. Step 2 happens 6 months later, when a hypervisor mi…
Alexander Zemskov
4 min read
MPLS is where the control plane and the forwarding plane most often disagree. The LSP is up in the CLI and the packets still go somewhere else. We test the two together: …
Alexander Zemskov
4 min read
An IGP has one job: tell every router where every link is, fast. The protocol is 30 years old and the implementations still differ by a factor of 10 in how quickly they d…
Alexander Zemskov
4 min read
A router datasheet says "BGP: 4M routes, 1,000 peers". The number is true in the sense that the table fits in memory. It says nothing about how long the box takes to inst…
Alexander Zemskov
4 min read
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