Multi-CDN means using two or more CDNs together and switching traffic between them — for resilience, regional coverage, and pricing leverage. No single CDN is best everywhere or immune to outages, so large platforms route each viewer to whichever CDN currently performs best in their region, and fail over instantly if one degrades.
The orchestration layer is what makes this work: it gathers real-time performance data (from client QoE beacons and synthetic monitoring), applies business rules (cost, commit levels, geography), and steers traffic via DNS, manifest manipulation, or a client-side switching SDK. Done well, it improves QoE and uptime while playing CDNs against each other on price.
The trade-offs are complexity and cache efficiency: spreading the same content across multiple CDNs can lower each one's cache-hit ratio and split volume below favorable commit tiers, so multi-CDN is a deliberate engineering and commercial decision, not a default for small platforms.
