透過您的圖書館登入
IP:44.199.212.254
  • 期刊

在電信乙太網路中提供高可用性及動態頻寬調整的Triple Play服務

Providing High Availability and Dynamic Bandwidth Allocation for Triple Play Services over Carrier Ethernet

摘要


隨著結合語音、視訊與數據的三合一(triple play)服務逐漸成熟,如何建構一個具備穩定傳輸品質的服務網路架構,是電信業者一直努力研究的課題。在本文中,我們提出一個在電信乙太網路(Carrier Ethernet)下,具備頻寬管理及高網路可用性的Triple play服務網路架構。此架構包含存取網路與IP/MPLS(internet protocol/multiprotocol label switching)核心網路。在存取網路中,我們將匯集在一條實體乙太網路線路的Triple play服務,利用虛擬網路(virtual LAN, VLAN)的技術將各服務虛擬隔離。爲有效利用網路頻寬,我們提出一服務限速結合監控管理的機制,透過策略決策路由器(policy decision router, PDR)佈置,動態調整各服務的限速,讓使用者未使用的閒置頻寬得以有效利用,並且讓各項服務品質獲得保證。爲了提高網路的可用性,我們在PDR的上鏈電路中導入多機箱鏈路聚合(multi-chassis LAG, MC-LAG)機制,以避免單一節點失效的問題。此外再經由多條虛擬專用區域網路服務(virtual private LAN service, VPLS)建立備援電路,並導入雙向轉發檢測(bidirectional forwarding detection, BFD)第三層連通性測試機制,讓我們能夠及早發現核心網路中斷處。並經由node-level與pseudowire-level保護機制的運用,提供網路中斷快速回復的特性。爲驗證所提架構的可行性,我們進行許多的模擬實驗,並比較傳統路由機制與所提的機制。模擬實驗發現,目前常用路由資訊協定(routing information protocol, RIP)及開放式最短路徑優先協定(open shortest path first, OSPF)的收斂時間,各需要180秒及30秒,並無法滿足我們對於Triple play服務中斷快速回復的要求,而我們所提之結合BFD與靜態路由協定的設定,只要1秒就可以發現網路發生中斷處,進而切換至備援路由。此外應用MC-LAG機制,只要2秒就可將訊務移轉至另一個網路節點。因此藉由各種機制的運作,本文提供滿足在電信乙太網路上穩定有效益的Triple play服務。

關鍵字

三合一服務 電信乙太網路 VPLS BFD

並列摘要


With the rapid growth of triple play (voice, video, and data) services, constructing a service network architecture with stable transmission quality is an urgent research topic. This paper proposes a triple play service network architecture with dynamic bandwidth management and high network availability over Carrier Ethernet. The proposed architecture consists of access networks and the IP/MPLS core network. In the access network, the traffic of triple play services in the same truck are virtually isolated using virtual LAN (VLAN) technology. To utilize the network bandwidth, a monitoring and control mechanism via a policy decision router (PDR) to dynamically adjust the bandwidth allocation for each service is adopted. To improve network availability, a Multi-Chassis Link Aggregation (MC-LAG) mechanism is introduced in the uplink route of PDR to prevent disconnection due to a single node failure. Establishing multiple VPLSs (virtual private LAN services) in the IP/MPLS core network and equipping a bidirectional forwarding detection (BFD) mechanism enables prompt discovery of the network disconnection. Through the application of both node-level and pw-level (pseudowire-level) protection schemes, a rapid network recovery can be facilitated. To verify the applicability of the proposed architecture, several experiments were conducted. Various routing mechanisms were tested since the discovery of route disconnection in the IP/MPLS core network is a complex and time-consuming task; for example, RIP requires 180 seconds while OSPF only requires 30 seconds to discover a network disconnection. A detection mechanism is developed by combining a static routing protocol and BFD mechanism. Using this mechanism, a disconnection in the IP/MPLS core network can be located in one second. Moreover, using the MC-LAG mechanism, the traffic can be redirected from an inactive node to the standby node in two seconds. The simulation results demonstrate that the architecture proposed in this study is suitable for triple play services.

並列關鍵字

triple play Carrier Ethernet VPLS BFD

延伸閱讀