Research Of Streaming Session Sharing And Streaming Protocol In Cluster Streaming Media Caching

With the explosive growth of the multimedia streaming service in the past few years, the traditional client/server topology architecture has the following problems: Firstly, with the increase of client, the load of streaming server is heavier and heavier, which causes the slow response for streaming server and can not guarantee the real-time of streaming service; Secondly, the increase of playback delay seriously affects the characteristics of streaming service; Thirdly, traditional modes such as one point(streaming server) vs multiple point(client) cannot share the different sessions, which consumes more bandwidths and heavies the load of streaming server; Lastly, under the poor WAN environment, this architecture can not provide stable and real-time streaming service.To address the problems mentioned above, not modifying the mode of client/server at all, this paper implements cluster-based streaming caching proxy server system with the technique of caching proxy server. In this system, we introduces cluster architecture to provide global and scalable streaming caching proxy service mechanism; We implement streaming media transfer protocol on caching proxy end; We implement layered caching mechanism (global disk caching and memory caching) using dynamic sharing running memory buffer algorithm to support more stable and real-time parallel streams; We implement client request aggregation by means of streaming session sharing to reduce disk I/O and serve more user; We propose single streaming image to support the unify of pre-fetching streaming and caching streaming, which guarantees the proxy streaming of transparency for client; We design and implement streaming pre-fetching mechanism based on packet feedback information to reduce the number of "rebuffering" on client end; We bring forward streaming caching admission control policy fit for streaming caching proxy server to guarantee the QoS of streaming service.Currently, there is not available streaming caching proxy server in China. Contrast to foreign streaming caching proxy server, our system has the following prominent advantages: (1) Introduced streaming session sharing mechanism supports more stable, real-time parallel streams; (2) Proposed dynamic shared running memory caching mechanism can provide the support for client request aggregation and streaming session sharing; (3) The Combination of prefix caching and segment-based caching techniques implement efficient streaming caching data accessing and management; Network pre-fetching policy and caching admission control mechanism improve the intelligence of streaming caching.We implement proxy system on the Linux platform with C/C++ language. The performance test presents that our system has excellent scalability, reduces the network delay and jitter during client playback and workload of streaming server. Additional our system improves the QoS of streaming service apparently.