Edge Cache and CDN Platform  ·  View 25 of 29  ·  6 · Operations

Unit Economics

How cost per delivered terabyte and cost per miss are calculated, and the volume at which the $4 target is realistic.

Editable source SVG draw.io All views
Inputs Transit + IX invoices 95th percentile Hardware ledger NetBox · 5-year life Colocation + power per rack per PoP Meter Delivered bytes property × PoP Origin bytes per path pattern Requests + purges Model Cost model ClickHouse · monthly Cost of a miss egress + transit + ms Publish $ per delivered TB target ≤ 4.00 Origin offload ≥ 98.5% of bytes n−1 headroom priced as insurance Decide Chargeback per business unit Offload breach > 1.5% origin bytes Unit Economics — What a Terabyte and a Miss Actually Cost External / third party Security / platform Data store Application we own Opportunity Decision point Risk / gap At 6 PB a month the fixed cost of 18 PoPs is near $30 per TB. The $4 target is realistic only near 45 PB, half of it peered. v 1.0 · owner FinOps · date 2026-09

The number that needs a decision

  • The requirement's figures do not fit together. 6 PB a month is an average of about 18.5 Gbps, which puts a 400 Gbps peak at about 22 times the average; delivery traffic usually peaks at 2 to 3 times. 250,000 requests per second at the 25 KB average response implied by 6 PB comes to about 50 Gbps, not 400.
  • At 6 PB a month, the fixed cost of 18 self-operated PoPs is about $180k a month, around $30 per TB. A commercial CDN would be cheaper at that volume. At about 45 PB a month, consistent with a 400 Gbps peak, the same estate costs around $5.50 per TB, and approaches $4 once half the bytes go over settlement-free peering.

Decisions

  • Hardware beyond the six tier-1 PoPs is not ordered until real traffic has been measured during the proof phase.
  • The cost of a miss is reported as origin egress plus shield transit plus added latency. A drop in hit ratio shows up as money in the monthly report.

Assumptions

  • Planning prices: servers amortised over 5 years, about $60k a month with network hardware; colocation and power about $60k; transit and exchange ports about $45k at 6 PB; control plane about $15k. Staff costs are excluded and belong in the build-or-buy comparison.
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Solution Architecture v1.0 · Edge Architecture · 2026-09 · 29 views · open source, fully on-premises25-unit-economics