Is transit the default path?

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

Does Sync on letter Y share fate with other letters?

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

Sync: capacity in Miami (MIA) · Y-40

Runbook Y-40 for Sync in Miami (MIA). Marker xserv-y-fcca718c4ecd. This page covers capacity for LATAM operators, not a worldwide average.

Sync: Failure modes we actually see

Capacity notes for y-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.

Sync: How this letter ties to the rest

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

Sync: A note on cost and transit

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

Sync rollback Y-06

Sync peering Y-07

Peering for Sync (y-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.

Sync cache Y-08

Cache rules for Sync on y-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.

Sync headers Y-09

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