Basis token consistency: supporting strong Web cache consistency

With web caching and cache-related services like CDNs and edge services playing an increasingly significant role in the modern Internet, the problem of the weak consistency and coherence provisions in current web protocols is drawing increasing attention. Toward this end, we differentiate definitions of consistency and coherence for web-like caching environments, and then present a novel web protocol we call “Basis Token Consistency” (BTC). This protocol allows compliant caches to guarantee strong consistency of content retrieved from supporting servers. We then compare the performance of BTC with the traditional TTL (Time To Live) algorithm under a range of synthetic workloads in order to illustrate its qualitative performance properties.