Edgecache

Edgecache is a caching layer positioned at the edge of a network to store copies of content or dynamic responses closer to end users. It is commonly deployed within content delivery networks and enterprise edge infrastructures to reduce latency, conserve bandwidth, and improve availability by serving repeated requests from nearby edge nodes rather than repeatedly contacting a centralized origin.

In operation, edge cache nodes reside in points of presence near users. When a client requests content, the nearest edge node checks its local cache. A cache hit serves the stored response directly; a cache miss triggers retrieval from the origin or another upstream cache, after which the response is stored for future requests according to the configured policy. Traffic routing and load balancing direct requests to appropriate edge locations to optimize performance and resilience.

Caching policies and content types are governed by directives such as cache-control headers and TTLs that define content freshness. Validation mechanisms like ETag and If-Modified-Since help determine whether cached content remains valid. Eviction policies, including LRU and LFU, manage limited storage. Edge caches may handle static assets, media, and API responses, and can incorporate prefetching or cache warming. Dynamic content can be cached with edge computing techniques that transform or personalize responses before they are stored.

Deployment models include traditional CDN edge caches and corporate proxy caches. Some edge architectures extend caching with compute at the edge, using edge workers or functions to generate or modify content before caching. Challenges include maintaining freshness, coordinating purges, preventing cache poisoning, and addressing privacy and security considerations, especially for sensitive data.