WAN: design in São Paulo (GRU) · W-25

Runbook W-25 for WAN in São Paulo (GRU). Marker xserv-w-343508af0cb7. This page covers design for LATAM operators, not a worldwide average.

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: 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 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.

WAN headers W-09

Headers for w-09 carry the letter, the region (GRU) and a request id. WAN debugging in São Paulo should not require a packet capture in Santiago first.