支援 IP 群播樹區域快速重新繞送機制之設計與效能分析

Design and Performance Evaluation of Local Fast Reroute Scheme for IP Multicast Tree

吳誌軒(Chih-Hsuan Wu)

指導教授 ： 蘇暉凱

國立虎尾科技大學/電機資訊學院/電機工程研究所/碩士(2012年)

https://doi.org/10.6827/NFU.2012.00057

摘要

近年來，因網路的快速發展，即時性多媒體的應用服務越來越多，如：IPTV、MoD 與 Video Conference，使得網際網路群播服務可使用性 (Network Availability) 越來越受重視，因此也成為網路服務業者 (Internet Service Provider, ISP) 的重要服務品質參數。目前，IP 網路處理網路中斷有兩種類型：IP Restoration 與 IP Protection。IP Multicast Restoration 是一種事後處理方法，當錯誤發生後，網路設備透過路由協定相互交換新的網路狀態，並學習新的路由資訊，在有其他存活路徑的情況下，恢復傳輸服務。而另一種，IP Multicast Protection 是一種事先主動分析網路路由方法，在網路設備損壞或線路中斷前，事先準備好各種處理方式，一旦網路中斷發生，立即將受影響的封包快速繞送到不受影響的節點上。我們以 PIM-SM (Protocol Independent Multicast – Spares Mode) 群播路由協定為基礎，Router 會根據所建立的 Multicast Tree 結構將 Multicast Packets 傳送至每一個 End User，一旦中間有連線斷線或 Router 損壞，下游所有 End User 將直接受到影響，損壞的部份如果越靠近 RP，受影響的程度越大。所以我們提出 Tree-Based 方法在 IP Multicast 的環境下來對於群播樹做區域的快速路由，並利用 ns2 模擬此機制與分析效能。我們將觀察封包遺失和控制訊息量，來分析比較與原本的群播路由協定傳輸效能的差異性，最後模擬數據部分在第五章節會說明成果。

關鍵字

PIM-SM ； 群播保護 ； 多點群播 ； 服務品質 ； 共享樹 ； 即時性

並列摘要

Recently, more and more real-time multimedia application services are provided over Internet, such as IPTV, MoD, Video Conference, etc. For the real-time multimedia applica-tions that network availability is one of the important QoS (Quality of Service) parameters in IP multicast transport networks. The two types of approaches to improve network resilience in the IP layer are IP restoration and IP protection. IP restoration attempts to find a new route by which to restore connectivity once a failure has occurred, e.g., Interior Gateway Protocol (IGP) routing recovery. IP protection, the intention of which is to achieve rapid recovery from failure (in just a few milliseconds), is based on fixed and predetermined failure recovery, where the selection of the next-hop is performed in conjunction with the identification of a backup for the next-hop. In IP multicast, they were very serious affected of real-time services when the failure happened in the multicasting tree of link or node. While the upper node or link in multicast tree has failure, it would affect all of downstream end-user. In this thesis, we pro-pose a Tree-Based Local Fast Reroute scheme for IP multicast tree with two algorithms for share-tree node protection and link protection in the intra-area multicast routing. Finally, the network simulator ns2 was used to demonstrate the performances of packet loss and control overhead.

並列關鍵字

Multicast protection ； Share tree ； QoS ； Real time

參考文獻

[1]W. Fenner, "Internet Group Management Protocol, Version 2," RFC 2236, Nov. 1997.

[2]D. Waitzman, S. Deering and C. Partridge, "Distance Vector Multicast Routing Protocol," RFC 1075, Nov. 1988.

[3]J. Moy, "Multicast Extensions to OSPF," RFC 1584, March 1994.

[4]C. Metz, "IP protection and restoration," IEEE Internet Comput., vol. 4, no. 2, pp. 97-102, Mar-Apr 2000.

[5]G. Iannaccone, C.-N. Chuah, S. Bhattacharyya, and C. Diot, "Feasibility of IP restoration in a tier 1 backbone," IEEE Network, vol. 18, no. 2, pp. 13-19, Mar-Apr 2004.