Is transit the default path?

No. Peering in Miami is default; transit to São Paulo is overflow and is billed that way.

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.

WAN: docs in Miami (MIA) · W-48

Runbook W-48 for WAN in Miami (MIA). Marker xserv-w-1018f903da1f. This page covers docs for LATAM operators, not a worldwide average.

WAN: A note on cost and transit

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: Why it matters on this continent

Design for WAN on letter W starts in São Paulo (GRU). Runbook w-01 keeps a single owner, a written rollback, and a traffic split that can be reversed without a global freeze. Neighbors in Santiago only take overflow after the local pool fails a health window.

WAN: How XServ runs it day to day

Probes for WAN (w-02) leave Santiago every 15s toward Bogotá. XServ pages the named owner if loss or RTT crosses the letter budget. A probe never shares a queue with bulk transfers, so a saturated WAN does not hide a dead PoP.

WAN design W-01

WAN probe W-02

WAN policy W-03

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 capacity W-04

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.