Patent attributes
Improvements to internet cache protocols are disclosed. In certain embodiments, a client-facing proxy server can query peer servers to determine whether they have a copy of an object that the proxy server needs. The peer servers can respond based on object information that the peer servers stored about objects they have in cache, where the peers recorded such object information previously when ingesting the objects into their cache and stored it separately from the objects for fast access (e.g. in RAM vs. on disk). This information can be expressed in a compact way using just a few object flags, and enables the peer server to quickly respond and with detail about the status of objects they hold. The proxy server can make an intelligent decision about which peer to use, and indeed whether to use a peer at all.
