CDNs use consistent hashing to determine which edge servers cache specific content to minimize misses when what happens?

CDNs use consistent hashing to determine which edge servers cache specific content to minimize misses when what happens?

• A. Centralized cache
• B. Fixed partitioning
• C. Random assignment
• D. CDNs using consistent hashing

Answer: (D)

Consistent hashing is used to keep cache mappings stable when the set of edge servers changes. In a CDN, content items are mapped to edge servers so that each item is served from a specific cache. With consistent hashing, when a server is added or removed, only a small subset of items gets remapped to different servers, while the majority stay on their current caches. This minimizes cache misses (and the need to fetch from origins) during topology changes. The best choice describes CDNs using consistent hashing, because that technique is precisely what enables reduced misses when the edge-server pool changes. In contrast, fixed partitioning would force large remappings on changes, and random assignment would sabotage locality, leading to more misses.

Consistent hashing is used to keep cache mappings stable when the set of edge servers changes. In a CDN, content items are mapped to edge servers so that each item is served from a specific cache. With consistent hashing, when a server is added or removed, only a small subset of items gets remapped to different servers, while the majority stay on their current caches. This minimizes cache misses (and the need to fetch from origins) during topology changes.

The best choice describes CDNs using consistent hashing, because that technique is precisely what enables reduced misses when the edge-server pool changes. In contrast, fixed partitioning would force large remappings on changes, and random assignment would sabotage locality, leading to more misses.