Payload caching: High-speed data forwarding for network intermediaries

Large-scale network services such as data delivery often incorporate new functions by interposing in-termediaries on the network. Examples of forward-ing intermediaries include rewalls, content routers, protocol converters, caching proxies, and multicast servers. With the move toward network storage, even static Web servers act as intermediaries to for-ward data from storage to clients. This paper presents the design, implementation, and measured performance of payload caching, a technique for improving performance of host-based intermediaries. Our approach extends the func-tions of the network adapter to cache portions of the incoming packet stream, enabling the system to forward data directly from the cache. We pro-totyped payload caching in a programmable high-speed network adapter and a FreeBSD kernel. Ex-periments with TCP/IP traÆc ows show that pay-load caching can improve forwarding performance by up to 60 % in realistic scenarios.