A Personal Internet Live-Broadcasting System
AISA '02 Proceedings of the First International Workshop on Advanced Internet Services and Applications
An expressive aspect language for system applications with arachne
Transactions on Aspect-Oriented Software Development I
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Most of the Web traffic today uses the HyperText TransferProtocol(HTTP), with the Transmission Control Protocol(TCP) as the underlying transport protocol. TCP provides severalimportant services to HTTP, including reliable data transfer andcongestion control. Unfortunately, TCP is poorly suited for theshort conversations that comprise a significant component of Webtraffic. The overhead of setting up and tearing down TCP stateamortizes poorly for these small connections. Moreover, emergingmodern Web server systems employ HTTP redirection for serverload-balancing and content distribution; such schemes requiresetting up (and tearing down) multiple TCP connections forservicing a single client request. We have designed and analyzed ahybrid scheme to address these issues. The scheme uses either TCP,or the User Datagram Protocol(UDP) as the underlyingtransport protocol for carrying Web traffic. UDP is used for shorttransfers (including HTTP redirection), while TCP is used for allother transfers. In this man-ner, we avoid the extra TCP overheadfor short connections, but still benefit from the reliable deliveryand congestion control that TCP provides. We ran trace-basedsimulations to quantify the effects of various net-work parameters(i.e., packet loss rates) on the performance of the hybrid scheme.We observed perfor-mance gains exceeding 20-250 with HTTP/1.1-stylepersistent connections, and over 40-500 without persistentconnections. These gains can be improved with further performanceoptimizations that we describe.