即時傳輸協定下負載平衡方法之研究

A STUDY OF LOAD BALANCING SCHEMES USING RTP

鄭世彬(Sh-Bin Cheng)

指導教授 ： 蔡佳勝

大同大學/電機資訊學院/資訊工程學系所/碩士(2008年)

摘要

隨著網路通訊協定的蓬勃發展，各種網路的相關應用也越來越多，其中更以即時性的網路多媒體服務為廠商主要發展的範疇，主要仍是以網際網路中現有的多媒體架構與訊息傳遞能力為基礎，提供整合視訊、語音、與其它多媒體通訊服務，達到多媒體通訊協定目的。但是當多媒體的內容越豐富，網路的頻寬也開始出現不足的情況，此外不穩定的網路頻寬也會嚴重影響到多媒體的服務品質。因此在這篇論文提出整合多網路介面頻寬，並且具有網路頻寬回饋的自調適負載平衡系統。允許 RTP 上的多媒體資料可以同時間在多條路徑上進行傳送。在傳送端，將原始的多媒體訊號來源，透過這篇論文所提出的負載平衡演算法作為封包分配的依據，且接收端可以透過 RTCP 回報 RTP 封包的傳送間隔時間，藉以動態的偵測網路頻寬的變化量。使發送端最終能動態依據網路的實際頻寬適當的調整負載平衡分配原則，因此可有效提整體網路使用率，同時提升資料傳輸量，最終達到提升多媒體串流穩定度及品質的目的。

關鍵字

頻寬分配機制. ； 多媒體服務品質

並列摘要

As communication networking becomes vital to people’s daily life, various communication protocols are evolved vigorously. The main push factor behind this network evolution is the real time transfer of multimedia information, such as, audio, image and video. Several protocols, such as RTP (Real Time Protocol) and RTCP (Real Time Control Protocol) are developed to facilitate the deployment of multimedia services in the Internet. However, as for the intention of deliver high quality of real time multimedia information, data transmission bandwidth becomes a major issue. Insufficient network bandwidth would also result in poor service quality. To overcome this obstacle, this thesis proposes an adaptive load balancing system that targets for intensifying overall network usage in a multi path network environment.
The proposed system uses a modified RTP header field to send packets through multiple paths in an RTP session. On the sender side, a suggested load balancing algorithm is used to perform RTP packet distribution. Meanwhile, the receiver side would utilize RTCP to notify senders on packet arrival intervals. Via the communication between sender and receiver, overall network bandwidth fluctuation is thus determined. By knowing the actual available network bandwidth, sender is then able to dynamically adjust packet distribution. Therefore, a load balancing system is achieved. This accomplishment would result in an increase to overall network throughput, thus, end users are able to enjoy stable multimedia services.

並列關鍵字

Bandwidth allocation mechanism. ； Multimedia quality of service

參考文獻

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[2] Jon Postel, “Transmission Control Protocol”, IETF RFC 793, September 1981.

[3] Jon Postel, “User Datagram Protocol”, IETF RFC 768, August 1980.

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