- 學位論文
在802.11環境中以SIP協定為基礎實現Push-To-Talk服務
Implementation of Push-To-Talk Service based on SIP Protocol over 802.11
摘要
Push-To-Talk (PTT)或稱PTT over Cellular (PoC)是電信業者所提供的類似無線電對講機的一項語音服務。近年來Session Initiation Protocol (SIP)在網際網路上的蓬勃發展，使PTT也能透過SIP這個協定在網際網路上得以實現。本文的目的是以校園無線網路 (802.11)為環境透過SIP來實現PTT系統，藉由802.11頻寬的優勢能夠得到比傳統電信網路 (第二代行動通訊、通用分組無線服務、第三代行動通訊)更好的網路反應時間，提升使用者使用上的觀感。在PTT 系統中，我們設計了三個服務控制：發話權、線上狀態、媒體控制，其中我們利用SIP來當作發話權、線上狀態控制的信令，並利用openSER來當作信令伺服器處理使用者的信令，並自行撰寫處理使用者媒體封包的媒體伺服器。本文也針對PTT伺服器進行效能上的評估，主要是觀察不同人數的使用者對於伺服器效能的影響，並且最後進行異質網路互連的測試。
並列摘要
Push-To-Talk (PTT), or PTT over Cellular (PoC) is a walkie-talkie like voice service provided by telecom operators. In recent years, thanks to developing of SIP that PTT service enabled on the Internet. In this paper, we design and implement the PTT System based on SIP protocol over 802.11 and we can get the better user experience utilized the benefits of bandwidth of 802.11 wireless network than in telecommunication network, such as 2G, GPRS, 3G. In our PTT system three service controls are designed: floor, presence, Control and SIP used as signaling in Floor, Presence control. The openSER as signaling server in our PTT System is to control the signaling of users and a Media Server custom-built we have. In order to understand the effect on different number of users, we estimate the performance of PTT server and tested the interconnection of heterogeneous networks.