Does Anycast on letter A share fate with other letters?

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

Where is Anycast measured first?

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

How fast is rollback for a-03?

The runbook is a command plus a named owner. There is no wait for a weekly change freeze.

Is transit the default path?

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

Anycast that keeps LATAM close to the answer

XServ announces the same service address from several cities so a packet lands on the nearest healthy node instead of crossing the continent.

Anycast: Why it matters on this continent

Design for Anycast on letter A starts in São Paulo (GRU). Runbook a-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.

Anycast: How XServ runs it day to day

Probes for Anycast (a-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.

Anycast: What operators should measure

Policy for Anycast is versioned as a-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.

Anycast: Failure modes we actually see

Capacity notes for a-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.

Anycast: How this letter ties to the rest

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

Anycast: A note on cost and transit

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

Anycast design A-01

Anycast probe A-02

Anycast policy A-03

Anycast capacity A-04

Anycast handoff A-05

Anycast rollback A-06

Anycast peering A-07

Peering for Anycast (a-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.

Anycast cache A-08

Cache rules for Anycast on a-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.

Anycast headers A-09

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

Anycast timeouts A-10

Timeouts on a-10 are tighter than the WAN RTT to Bogotá. Anycast in Santiago fails fast and retries once; a third try needs a human because it is no longer a blip.

Anycast regions A-11

Region names on a-11 match DNS and tickets: Bogotá / BOG, with Miami as the documented pair. Anycast dashboards never say “LATAM” as if it were one RTT.

Anycast docs A-12

Public docs for letter A stay aligned with identifier xserv-a-pack. Page a-12 is the Anycast slice operators search before the homepage. Edits in Miami show up in São Paulo on the next publish.