Synopsis

This chapter explains how compliance and data residency requirements shape a multi-CDN deployment. It describes how to constrain routing by jurisdiction, how to handle telemetry and logs without exporting sensitive data, how to align encryption and key custody with regional obligations, and how to verify behavior in production. The objective is predictable data location and lawful processing without degrading reliability or performance.

Scope and regulatory context

Compliance spans content delivery, control planes, logs, real user measurement, and provider support systems. Obligations arise from privacy laws, sector rules, contracts, and customer commitments. Multi-CDN introduces additional processors and network paths. Architecture and operations must express where data is processed, where it is stored, who accesses it, and how long it is retained. The model treats providers as processors under documented agreements and keeps data flows narrowly defined.

Data classification and flows

Delivery traffic includes objects and metadata such as client IPs, user agents, and headers. Telemetry adds timing and outcome fields. Some deployments include identifiers in headers or query parameters, which increases sensitivity. A practical approach classifies data into content, operational telemetry, and personal data. Each category receives an allowed processing location, retention targets, and access rules. Diagrams and data maps accompany configuration so engineers and auditors share the same picture.

flowchart TD Client[Client] --> Edge[CDN edge in Region A] Edge --> Origin[Origin or shield in Region A] Edge --> TelemetryA[Regional telemetry bucket A] subgraph Control Policy[Residency policy and contracts] end Policy --> Edge Policy --> TelemetryA Edge -. blocked .-> RegionB[CDN edge in Region B] note right of Edge: Routing constrained by policy

Residency constraints in routing

Jurisdictional routing ensures that requests originating in a region are served by edges and origins within that region when policy requires it. Enforcement occurs in the steering layer. DNS based steering maps resolver geography and ASN to regional candidates. A layer 7 proxy applies jurisdiction rules per request using client IP classification with conservative fallback. Client side logic reads server hints and respects residency decisions. When geography cannot be resolved confidently, the route that complies with the strictest rule is selected. Residency rules precede health and performance rules, and their precedence is published so later changes do not weaken enforcement.

Logs, telemetry, and analytics

Operational visibility remains necessary under residency. Collection focuses on fields required for correctness and reliability. Telemetry is aggregated at the regional level, with raw logs retained locally for short periods and then reduced to derived series. Identifiers are minimized, truncated, or hashed with keyed functions stored under regional key management. Export of raw logs across regions is avoided. Where global insights are needed, export uses pre-aggregated, privacy-preserving statistics. Data schemas document field purpose and sensitivity so queries and dashboards avoid accidental disclosure.

flowchart LR EdgeA[Edge logs EU] --> LocalEU[Regional storage EU] EdgeB[Edge logs US] --> LocalUS[Regional storage US] LocalEU --> AggEU[Aggregate metrics EU] LocalUS --> AggUS[Aggregate metrics US] AggEU --> Global[Global rollup without identifiers] AggUS --> Global note bottom of Global: No raw cross-border transfer

Encryption and key custody

Transport security is uniform across providers with TLS and modern protocols. At rest encryption applies to regional buckets and logging stores. Key custody aligns with residency by using regional key management that does not export keys outside the region. Mutual TLS or signed headers protect the origin path. Certificate and token rotation processes operate per region and record custody so audits can verify that secrets and keys remain under the declared jurisdiction.

Access control and processor management

Providers and subcontractors act under written terms that define roles, processing purposes, security measures, and breach notification timelines. Access to operational consoles and log stores follows least privilege with regional scopes. Administrative access from outside a region is either prohibited or mediated through controlled break-glass procedures with recorded approvals. Processor lists, subprocessor changes, and data center locations are tracked so risk assessments remain current.

Cross-border transfers

Some deployments require transfer mechanisms such as standard contractual clauses or equivalent instruments. Architecture reduces transfers to the minimum by keeping delivery, logging, and telemetry local. Where transfers remain, data is minimized and protected by encryption in transit and at rest with keys held in the destination region. Control planes that compute global policies avoid including personal data in requests to providers.

Testing and verification

Residency behavior is verified continuously. Synthetic probes originate from in-region and out-of-region vantage points and assert the selected route and serving region. Edge headers and logs carry region and provider identifiers that allow confirmation without leaking user data. Periodic audits compare data maps with observed storage locations and access trails. Failures to comply trigger routing blocks or storage policy changes before incident reports are required.

Failure and fallback behavior

When a region experiences provider degradation, isolation must prefer alternatives within the same jurisdiction first. Only when no compliant route exists does policy allow cross-region failover, and only under documented emergency criteria with explicit time limits and notifications. Control planes record each exception with scope and justification. Restoration removes exceptions in reverse order.

Instrumentation that collects client-side data respects consent models and regional defaults. Sampling rates and fields differ by region when rules require it. Collected data avoids full URLs when they may contain identifiers. Where IP addresses are used for geography, truncation happens at collection time. Scripts hosted on providers follow the same residency routing and do not beacon to out-of-region endpoints.

Documentation and audits

Evidence includes data flow diagrams, lists of processors and subprocessors, routing precedence rules, storage locations, retention schedules, access logs, and test results. Documents live with configuration in version control so changes are peer reviewed and auditable. Incident reviews include a residency section that confirms whether controls held under stress.

Operations

Configuration changes that affect routing, logging, or storage include a residency impact note. Dashboards display regional compliance status with signals for cross-region traffic, telemetry exports, and key access by geography. Playbooks include steps to pin traffic within regions, rotate keys locally, disable non-compliant features, and notify stakeholders. Provider contracts describe data handling, breach response, and regional coverage so the technical plan matches commercial commitments.

Routing precedence and enforcement appear in /multicdn/traffic-steering/. Telemetry collection and aggregation appear in /multicdn/signals-telemetry/. Origin access controls and mutual authentication appear in /multicdn/origin-architecture/ and /multicdn/security-parity/.

Further reading

Privacy and security frameworks such as GDPR, ISO 27001, and SOC reporting describe obligations for processors and controls for data handling. Public references from national regulators provide regional guidance on data residency expectations and cross-border transfer mechanisms.