Using Signatures to Improve URL Routing

World Wide Web Content Distribution Networks (CDNs) are these days being supported by devices that have the ability to route at layers that lie higher up than the IP layer. This paper looks at URL routing and how it can be used to forward or redirect a client HTTP request to the best available content source. The paper develops and evaluates a new method for URL look up that uses fixed-length URL signatures based on CRC32 coding of URLs. With the implementation of URL signatures, one is able to find smaller update messages, smaller routing tables, and faster lookups. The paper also shows how the circuit used to generate an Ethernet packet CRC32 and how it can be simultaneously used to generate the CRC32 of a URL within an HTTP request. The paper evaluates signature collisions along with CPU resources that are required to generate signature URL lists, URL list size, look-up performance, and TCP connection performance. At the same time, these URL signatures use nine representative server and cache traces.