新一代網路影音傳輸協定之研究與實作(C2C)

隨著網路頻寬的增加以及無線網路的普及，IP位址的需求量也越來越多，NAT成為了一個很簡單的解決辦法。它除了能解決IPv4網路位址不足的問題，也可以保護NAT內的私有網路用戶不受外部公眾網路的駭客進行破壞攻擊，所以即使未來IPv6能完全取代IPv4網路，NAT也不會因此而淘汰，其仍有存在的價值。但也因為這樣的保護措施，同時也影響到P2P通信領域的發展。現今國際標準組織IETF制定的SIP或RTSP等網際網路公認協定之運用也越來越普遍，但這些協定往往並沒考慮到NAT產生的問題，造成無法達到真正P2P通信，即使後來IETF也針對NAT穿越問題制定了STUN，但該方法遇到一些特殊行為的NAT，仍會導致穿越失敗，因此本論文針對NAT的特性做深入的研究，並針對研究結果在NAT穿越上設計一套點對點通訊協定C2C(Client to Client)，改善了STUN在NAT穿越上的不足。 C2C協定同時也是一套具模組化的函式庫，該函式庫可以搭載在SIP或RTSP中，利用函式庫建立P2P通道，並把資訊提供給控制SIP或RTSP使用者使用，而且系統不只小且輕量，對於網路開發業者可以在不動SIP或RTSP等核心程序下，以最低成本來完成P2P通信；而C2C協定同時也可以取代SIP或RTSP等協定，可以完全獨立交換雙方彼此的重要資訊。

關鍵字

NAT ； P2P ； NAT UDP Traversal ； NAT Port Prediction ； C2C Protocol

並列摘要

As network bandwidth increases and the popularity of wireless networks, IP addresses demand become more and more, so NAT has also become a very simple solution. NAT can solve the problem about the shortage of IPv4 network address, and it can also protect users within the private network from hacker’s attack on external public network. So even if IPv6 can completely replace IPv4 network in the future. NAT also will not be eliminated, its value is still there. But such protection measures also affects the P2P communication fields. SIP, RTSP and other protocols developed by IETF are increasingly common today. However, these protocols does not take the NAT issues into account, so that they are hard to achieve P2P communication. Even though the IETF developed the STUN for NAT traversal, but this method encounters some special behavior of NAT, it still cause failure. Therefore, this thesis focuses on NAT features for a detailed study, and develop a brand-new protocol C2C (Client to Client) to improve STUN solution. C2C protocol is also a modular library of API, it can be implemented to a product, and mounted on SIP or RTSP. P2P channel can be established by C2C in advance and to provide the information to SIP or RTSP users. And the system is not only small and lightweight. For some network development industry, they don’t need to modify the SIP or RTSP core. They can cost down to complete the P2P. C2C also can replace SIP or RTSP and other protocols. It can be completely independent too.

並列關鍵字

NAT ； P2P ； NAT UDP Traversal ； NAT Port Prediction ； C2C Protocol

參考文獻

[2] 鐘建宇，「NAT穿透法於SIP通訊協定之研究與實作」，國立台北科技大學碩士論文，民國九十六年六月，第17頁。

[4] Andreas Muller, and Georg Carle, “Behavior and Classification of NAT Devices and Implications for NAT Traversal”, Technische Universitat Munchen, Andreas Klenk, Universitat Tubingen, 2008. (references)

[1] 賈文康，「SIP會談啟始協議操典」，松崗，2008，第2章12-16頁。