Caching the uncacheable: CloudFlare's Railgun

Cloudflare, a popular content delivery network, has introduced a premium service called Railgun that aims to speed up the delivery of web content that cannot be cached. The primary advantage of using Cloudflare is its ability to cache and deliver static content from data centers around the world, improving latency issues for users globally. However, only about 66% of website content can be cached, with the remaining 34% requiring retrieval from the origin web server. Railgun addresses this issue by using a scheme that dramatically reduces bandwidth usage and improves download times for dynamic or personalized web pages. It achieves this by recognizing that uncacheable web pages do not change rapidly and uses this fact to achieve high compression rates, similar to video compression techniques. The technical details of Railgun involve two components: the sender and the listener, which establish a permanent TCP connection secured by TLS for the Railgun protocol. This system allows multiple HTTP requests to be run simultaneously and asynchronously across the link, resulting in significant performance improvements compared to standard gzip compression methods.