This letter presents the implementation results of an application-level cache file system, MCFS, which is specifically designed to provide efficient caching and transmission mechanisms for streaming media. The file system is built on a virtual file disk which is constructed as a single large file on a general-purpose file system. MCFS suits the access requirement of continuous media caching and provides an efficient I/O mechanism for cache servers. The experimental results show that MCFS outperforms the comparison model and provides a consistent I/O bandwidth.

In this paper, we present a CDN (Content Delivery Network) architecture for mobile streaming service in which content segmentation, request routing, pre-fetch scheduling, and session handoff are controlled by SMIL (Synchronized Multimedia Integration Language) modification. In this architecture, mobile clients simply follow modified SMIL files downloaded from a portal server; these modifications enable multimedia content to be delivered to the mobile clients from the best surrogates in the CDN. The key components of this architecture are 1) content segmentation with SMIL modification, 2) on-demand rewriting of URLs in SMIL, 3) pre-fetch scheduling based on timing information derived from SMIL, and 4) SMIL updates by SOAP (Simple Object Access Protocol) messaging for session handoffs due to client mobility. This architecture enhances streaming media quality for mobile clients while utilizing network resources efficiently and supporting client mobility in an integrated and practical way. The current status of our prototype on a mobile QoS testbed "MOBIQ" is also reported in this paper.