Just a guess on my part here, () may or may not exist . This is not a perfectly exact representation of the system, as in reality many steps here are recursivel

Just a guess on my part here, () may or may not exist . This is not a perfectly exact representation of the system, as in reality many steps here are recursively recalled, and for most steps the CPU and disk phases occur. I've certainly missed many. ( Application DNS cache) -> ( libc DNS cache ) -> ( gateway DNS cache ) -> ( DNS caching resolver cache ) -> ( DNS nameserver authoritative cache ) -> Filesystem Cache -> Hard disk Device Cache -> ( JavaScript JIT cache ) -> HTTP cache -> HTTP push cache -> HTTP Preload cache -> CPU L1 -> CPU L2 -> (CPU L3) -> ( HTTP proxy cache ) -> (N hops invoking many of these steps N times) -> ( HTTP router/relay cache ) -> ( HTTP Reverse Proxy cache ) -> HTTP Server request caching. Because on some hops almost all of them are invoked for a request, we aren't looking at 20 caches, we are looking at hundreds.