Does WAN on letter W share fate with other letters?

The control plane is shared. Data-plane queues for WAN stay isolated, so incident w-01 cannot drain neighbor letters.

Where is WAN measured first?

From Santiago (SCL) toward Bogotá. A global average is not an SLO for letter W.

WAN: headers in São Paulo (GRU) · W-45

Runbook W-45 for WAN in São Paulo (GRU). Marker xserv-w-bc86873644ff. This page covers headers for LATAM operators, not a worldwide average.

WAN: What operators should measure

Policy for WAN is versioned as w-03. Operators measure error rate, p95 from Bogotá, and time-to-rollback — not a worldwide average. Changes land in Bogotá first, then Miami, with a hold if either region regresses.

WAN: Failure modes we actually see

Capacity notes for w-04 assume rainy-season power in Miami and festival peaks toward São Paulo. The failure we actually see is a single uplink, not a cartoon partition of the whole continent. Spare ports and a second provider sit on the same runbook.

WAN: How this letter ties to the rest

Handoff from letter W WAN into the rest of the platform uses the same request IDs as the gateway. Runbook w-05 names who accepts the ticket after São Paulo pages out. Santiago does not silently inherit the incident.

WAN handoff W-05

WAN rollback W-06

Rollback for w-06 is a documented command, not a hope. Transit is billed as backup while WAN prefers peering in Santiago. If cost spikes, the runbook cuts overflow to Bogotá before touching customer prefixes.

WAN peering W-07

Peering for WAN (w-07) prefers the IX fabric that already carries last-mile ISPs in Bogotá. Session counts and prefix limits are on the same page as the Miami backup path.

WAN cache W-08

Cache rules for WAN on w-08 keep language-correct objects near Miami. São Paulo is a sibling cache, not an origin. TTLs are short enough that a bad asset does not live through a weekend.