MPLS網路上OAM功能的設計與實現

當網路發展至今，封包網路和電路網路之間的界線越來越模糊，原本的電路網路設計為傳輸電路交換應用的服務，像是音訊和視訊之類的資料，漸漸移轉到乙太網路和IP網路上，可是這些轉變太迅速了，使得原本規劃於電路交換網路的網路管理與運作(Operation, Administration and Maintenance)功能，像是SONET/SDH的訊框管理位元，變得無法完整的支援和實現於封包網路。為了維持和電路交換網路相同的網路品質，因此需要新的方法提出。 ITU-T分別在Y.1710點出多協定標籤交換(MPLS)上網路管理與運作所需的基本功能，並在Y.1711說明進一步的實現方式，透過四種增加的封包格式，CV(connectivity verification)、FFD(fast failure detection)、BDI(backward defect indication)、FDI(forward defect indication)來監控現在網路情形和傳播已發生的錯誤給上下游的路由器以便做處理，如重路由、轉換成備份路徑這類的後續動作。本篇論文將建構在這基礎之上，並加以改進和加強及實現。利用硬體較高的處理速度把上述的功能硬體化，此篇論文設計出可以同時維護三十二條LSP(label switched path)連結在每秒四十億位元多協定標籤交換網路上的晶片，內部頻率為一百二十五百萬赫茲，並且將詳細描述設計的概念和內部架構。此外增加兩類功能封包：啟動/停止(Activation / Deactivation)和(Performance Management)。第一類的功能為讓使用者更容易啟動或停止網路管理與運作功能，可以在遠端利用特定的封包改變更動網路管理與運作的狀態。並且加入表現管理的功能，其中提供輸出量、延遲、jitter、封包遺失率這些即時的基本數據，利用這些數據可以進行統計和分析，檢查是否現行的網路有達到服務水準協定 (Service Level Agreement)的要求，甚至預測現在的網路趨勢而先行找到對應的處理方式，例如此條連結將會發生壅塞，而路由器將盡快選擇其他的路徑以確保封包能順利送達目的地。

關鍵字

網路管理與運作；多協定標籤交換

並列摘要

As the development of network technologies, the difference between packet networks and circuit networks is much vaguer. Earlier networks are mostly circuit-switched based and are designed for circuit-switched applications, like voice and video. For now, the service of IP packet has played more and more important role than before. The OAM functions on the circuit-switched network are not enough in the packet-switched networks. In order to maintain the same network quality, new network architectures are required. ITU-T proposed MPLS network and defined the MPLS OAM basic requirement in Y.1710. Furthermore, in Y.1711 it pointed out four kinds of OAM functions, CV (connectivity verification), FFD (fast failure detection), BDI (backward defect indication) and FDI (forward defect indication) to monitor the current network status and transmit the defect information to the upstream and downstream routers for remedies, such as rerouting or switching to backup path. In addition, we defined two extra OAM functions, Activation /Deactivation and Performance Management. The first one that provides a remote control capability is able to set the OAM configuration easily. The second one is for performance purpose. This function provides a feedback mechanism of the traffic conditions regarding to throughput, delay, jitter, and packet error rate. From those collected data, the router could avoid defects in near future by analyzing and predicting the network traffic. In this thesis, we proposed an OAM architecture with enhanced performance management functionalities for MPLS networks. This work is capable of maintaining 32 LSP links in 4Gbps MPLS networks and the targeted operating frequency is 125MHz. This design is implemented using 0.18um CMOS technology.

並列關鍵字

MPLS ； OAM

參考文獻

[1] E. Rosen et al., “Multiprotocol Label Switching Architecture”, IETF RFC 3031, Jan. 2001.

[2] Prabagaran, R., Evans, J.B., “Experiences with class of service (CoS) translations in IP/MPLS networks”, LCN 2001. 26th Annual IEEE Conference on 14-16 Nov. 2001 p: 243 – 249.

[3] ITU-T Rec. Y.1711, “Operation & Maintenance Mechanism for MPLS Networks”, Feb. 2004.

[5] Lawrence, J., “Designing multiprotocol label switching networks”, IEEE Communications Magazine, Vol.39, Issue 7, Jul. 2001 p: 134 – 142.

[10] Aggarwal, R., “OAM mechanisms in MPLS layer 2 transport networks”, IEEE Communications Magazine, Vol. 42, Issue 10, Oct. 2004 p: 124 – 130.

國際替代計量

MPLS網路上OAM功能的設計與實現

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