Prefetching the Means for Document Transfer: A New Approach for Reducing Web Latency

User-perceived latency is recognized as the central performance problem in the Web. We systematically measure factors contributing to this latency, across several locations. Our study reveals that DNS query times, TCP connection establishment, and start-of-session delays at HTTP servers, more so than transmission time, are major causes of long waits. Wait due to these factors also afflicts high-bandwidth users and has detrimental effect on perceived performance. We propose simple techniques that address these factors: (i) pre-resolving host-names (pre-performing DNS lookup), (ii) preconnecting (prefetching TCP connections prior to issuance of HTTP request), and (iii) pre-warming (sending a “dummy” HTTP HEAD request to Web servers). Trace-based simulations demonstrate a potential to reduce perceived latency dramatically. Our techniques surpass document prefetching in performance improvement per bandwidth used and can be used with non-prefetchable URLs. Deployment of these techniqu...

• Type: Conference
• Year: 2000
• Where: INFOCOM
• Authors: Edith Cohen, Haim Kaplan
• Keywords: Communications, INFOCOM 2000, TCP Connections, User-perceived Latency, Web Servers