於現行的Web雙向通訊協定技術（Bi-directional web technologies）之中，以WebSocket效率優於其他Web雙向通訊技術（例如：Ajax），並在2011年由IETF定為通訊協定標準RFC 6455，以及W3C將WebSocket API列入為HTML5的標準。 本論文專注於WebSocket通訊協定的效率討論，在互動性影音傳輸服務或WebTV使用WebSocket通訊協定的情況下，不同使用者點閱同一部影音資料時，會造成相同資料的重複傳輸，因此本論文運用WebSocket代理伺服器實作群組頻道機制，以及伺服端動態快取機制，用以改善資料重複傳輸的問題。 群組頻道機制，利用使用者端請求達到驅動共用頻道，相同頻道請求的使用者，即可合併伺服器端相同資料的連線，將使用者端視為群組傳播，使之可用於節省網路頻寬，但其有完全相同連線才能合併的限制，因此本文再發展另一伺服端動態快取機制。伺服端動態快取則是利用伺服器端回應以驅動快取，若無共用分享下會增加額外快取控制的頻寬負擔，需要留意快取控制傳輸的效益。 本論文也討論群組頻道及伺服端動態快取的分散式架構，使這兩種機制均可運用於互動性影音傳輸服務或WebTV，助於提升WebSocket通訊協定使用的效率，使得WebSocket通訊協定更適合運用於頻寬成本較高的網路環境中。; With current bi-directional web technologies, the efficiency of WebSocket is superior to other bi-directional web communication technologies (for example: Ajax). In 2011, it was defined by IETF as the RFC 6455 standard, and WebSocket API has been incorporated by W3C as a standard for HTML5.
This paper focuses on the discussion of the efficiency of WebSocket protocol. When WebSocket is used for interactive video services or WebTV, access to the same video from different users causes repeated transmission of the same data. Therefore, in this paper, WebSocket proxy is utilized as a mechanism to group channels and another server Active Cache mechanism is to resolve the issue of repeated data transmission.
The group channel mechanism is driven by the request of end users. When users make request on the same channel, the connection to the same information on the server can be merged, and information can be transmitted to the users as a group to save network bandwidth. However, it is limited by the fact that only completely identical connection can be merged. Therefore, another server Active Cache mechanism is developed. It works by initiating caching based on response from the server. Although it can resolve the limitation on the channel grouping mechanism, it creates additional bandwidth load because of caching control. Therefore, there is a need to discuss the benefits of transmission via caching control.
This paper also discusses the distribution architecture of both mechanisms in order to improve the efficiency of WebSocket protocol application and make WebSocket protocol more suitable for network environment with high bandwidth cost.
