What is Multi CDN?
Multi-CDN, short for Multiple Content Delivery Networks, combines different CDNs from more than one provider into a single network.
When installed and implemented correctly, multi-CDNs can provide greater flexibility, availability, and performance compared to a single CDN. Multi-CDN approaches are also good at reducing latency and increasing flexibility in terms of choosing separate providers for different use cases.
The Working of Multi-CDNs
Multi-CDN operational workflow involves routing traffic selectively over multiple CDNs in a single network. Different routing decisions are made on the basis of different Multi-CDN strategies and implementations.
Common strategies include:
- Static DNS: In this approach, static DNS entries must be set up or configured for different CDNs in the multi-CDN setting. This method is relatively simpler but requires manual intervention in different situations.
- Managed DNS: It follows the same framework as static DNS. The only difference is that Managed DNS adds a layer of intelligence to the earlier approach. A lot of manual work is removed because of the smart routing technology.
- Round-Robin: This is a simple approach where a request is sent directly to the next CDN in the queue.
- Geolocation: Here, the criteria for choosing CDNs depend on the geolocation factors. For every request, the CDN where the PoP is geographically closest to the user will respond first.
- Variable-Driven Load Balancing: Here, routing decisions are based on various variables like cost, performance, location, weights, etc.
Pros of Multi-CDN
- Improvement in performance.
- Greater resilience.
- More flexibility because of the greater degree of control available.
- Offers greater vendor management and cost control features.
- Multi-CDN approaches are more complicated and involve complex processes.
- The single-CDN approach is much cheaper than the multi-CDN approach.
- Only larger applications that are more sensitive to downtime are good for Multi-CDN.