Is transit the default path?

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

Does Zones on letter Z share fate with other letters?

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

Zones: cache in Miami (MIA) · Z-68

Runbook Z-68 for Zones in Miami (MIA). Marker xserv-z-e227271c666c. This page covers cache for LATAM operators, not a worldwide average.

Zones: How XServ runs it day to day

Probes for Zones (z-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.

Zones: What operators should measure

Policy for Zones is versioned as z-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.

Zones: Failure modes we actually see

Capacity notes for z-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.

Zones handoff Z-05

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

Zones rollback Z-06

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

Zones peering Z-07

Peering for Zones (z-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.

Zones cache Z-08

Cache rules for Zones on z-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.