基于逐跳转发方式的单故障路由保护方法

业界提出利用LFA（loop free alternates）方案来应对网络中频繁出现的故障，然而LFA并不能保护网络中所有可能出现的单故障情形。针对上述问题，提出了一种基于逐跳转发方式的单故障路由保护算法SFRPA（single failure routing protection algorithm based on hop by hop forwarding）。SFRPA首先提出了三个无环路备份下一跳选取规则，然后制定了优先级队列的操作规则，最后利用优先级队列和无环路备份下一跳选取规则为所有源目的节点对计算出一个最优的备份下一跳。该算法具有支持逐跳转发、支持增量部署、保护网络中所有可能的单故障情形三个特征。实验结果表明，与经典的路由保护方案LFA、DMPA、TBFH和IAC相比较，SFRPA不仅可以应对网络中所有可能的单故障情形，并且具有较小的路径拉伸度。

Single failure routing protection algorithm based on hop by hop forwarding

The industry proposes to use the LFA scheme to cope with the frequent failures in the network. However, LFA cannot protect all possible single failure scenarios in the network. In response to the above problem, this paper proposed a single failure routing protection algorithm based on hop-by-hop forwarding(SFRPA). SFRPA firstly proposed three loop-free backup next-hop selection rules, and then formulated the operation rules for priority queues. Finally, it used the priority queue and loop-free backup next-hop selection rules to calculate an optimal backup next hop for all source-destination pairs. The algorithm has the following characteristics: supports hop by hop forwarding, supports incremental deployment, and protects all possible single failure scenarios in the network. The experimental results show that compared with the classical routing protection schemes LFA, DMPA, TBFH and IAC, SFRPA can not only deal with all possible single failure situations in the network, but also has less path stretch.