Multi-layer protection in IP-over-WDM networks with and with no backup lightpath sharing
Multi-layer protection in IP-over-WDM networks with and with no backup lightpath sharing
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DOI：
10.1016/j.comnet.2005.04.011
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发表时间：
2006-02
期刊：
影响因子：
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通讯作者：
Q. Zheng;G. Mohan
中科院分区：
文献类型：
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作者：
Q. Zheng;G. Mohan
本文研究了IP-over-WDM网络中的多层保护问题。在我们的多层保护方案中，根据恢复时间要求，在光路级别或标签交换路径（LSP）级别保护流量。在光路级保护中，路径（LSP）上的业务通过在主要光路上路由它来保护，主要光路在光学层处由它们各自的备份光路保护。在LSP级保护中，主LSP上的流量在IP多协议标签交换（MPLS）层由备份LSP保护。在这种情况下，主LSP和备份LSP都穿过不受保护的光路。我们允许两个备份LSP共享带宽资源，这些未受保护的光路，如果他们的主LSP是链路不相交的。在光路级保护中，备份资源是否可以共享取决于所使用的保护机制。在1：1专用保护中，备用光路在设置相应的主光路时预先配置，共享是不可能的。然而，在共享保护中允许共享，其中仅在故障之后配置备用光路。我们考虑这两种方案，并将其称为多层保护与无备份光路共享（MLP-NLS）和多层保护与备份光路共享（MLP-LS）。提出了一种层间共享（ILS）方法，通过允许备份LSP使用专用备份光路来提高MLP-NLS中的资源利用率。提出了两种综合路由算法，分别用于光路级保护和LSP级保护中的路径选择，以有效利用网络资源。我们通过NSFNET和泛欧网络上的仿真结果验证了所提出的多层保护方案的有效性。
We consider the problem of multi-layer protection in IP-over-WDM networks. In our multi-layer protection schemes, traffic is protected either at the lightpath level or at the label switched path (LSP) level based on the restoration time requirements. In lightpath-level protection, traffic on a path (LSP) is protected by routing it over primary lightpaths which are protected at the optical layer by their respective backup lightpaths. In LSP-level protection, the traffic on a primary LSP is protected at the IP-multi-protocol label switching (MPLS) layer by a backup LSP. In this case, both primary and backup LSPs traverse unprotected lightpaths. We allow two backup LSPs to share bandwidth resource on these unprotected lightpaths if their primary LSPs are link-disjoint. In lightpath-level protection, whether backup resources can be shared or not depends on the protection mechanisms used. In 1:1 dedicated protection where the backup lightpath is pre-configured at the time of setting up of the corresponding primary lightpath, sharing is not possible. However, sharing is allowed in shared protection where the backup lightpaths are configured only after failure. We consider these two schemes and refer them as multi-layer protection with no backup lightpath sharing (MLP-NLS) and multi-layer protection with backup lightpath sharing (MLP-LS). An inter-level sharing (ILS) method is proposed to improve resource utilization in MLP-NLS, by allowing dedicated backup lightpaths to be used by backup LSPs. Two integrated-routing algorithms are developed to select paths in lightpath-level protection and LSP-level protection with the objective to utilize the network resources efficiently. We verify the effectiveness of the proposed multi-layer protection schemes through simulation results on the NSFNET and Pan-European networks.