Is transit the default path?

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

Does QoS on letter Q share fate with other letters?

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

QoS: cache in Miami (MIA) · Q-44

Runbook Q-44 for QoS in Miami (MIA). Marker xserv-q-7986ac3f65cf. This page covers cache for LATAM operators, not a worldwide average.

QoS: How XServ runs it day to day

Probes for QoS (q-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.

QoS: What operators should measure

Policy for QoS is versioned as q-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.

QoS: Failure modes we actually see

Capacity notes for q-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.

QoS peering Q-07

Peering for QoS (q-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.

QoS cache Q-08

Cache rules for QoS on q-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.

QoS headers Q-09

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

QoS timeouts Q-10

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