Fibbing is a network technology that can provide flexible routing in IP networks. In a Fibbing network, the network controller cleverly broadcasts link state advertisements (LSAs) of the open shortest path first (OSPF) protocol to generate fake nodes. These fake nodes enlarge the physical topology and turn the network into a virtual network. Although the routers still follow the shortest path routing in the virtual network, the flows are steered along the desired paths in the physical network. Even though a Fibbing network is capable of flexible routing, methods to achieve fast failure recovery have not been well studied. Conventionally, an IP network running the OSPF protocol takes a long time to converge after a failure occurs. The IETF proposed loop-free alternate (LFA) IP fast reroute technology to speed up failovers. However, we discovered that LFA technology is incompatible with Fibbing. The direct application of LFA technology in a Fibbing network will generate traffic loops. In this work, we propose a novel monitoring-cycle-based approach for fast failure recovery. By examining the liveness of the monitoring cycles, the system controller can promptly identify a failed link or a failed node and then perform traffic rerouting. Due to the properties of IP packet forwarding, a monitoring cycle in an IP network must be a simple cycle. We prove that any network that is both 2-vertex- and 3-edge-connected (2V3E) possesses a set of monitoring cycles that can be used to detect and identify any single link failure. In conjunction with the status pattern provided by the monitoring cycles, any single node failure can be detected by introducing an additional probe message. We propose an algorithm to obtain these monitoring cycles and design and implement a Fibbing controller for the network. To evaluate the performance of the proposed approach, we construct a physical testbed and an emulation network. The experimental results show that the proposed system works stably and can achieve a fast failover within a short period of time.

中文翻译：

---

光纤网络的快速故障恢复方案

光纤是一种网络技术，可以在IP网络中提供灵活的路由。在Fibbing网络中，网络控制器会巧妙地广播开放式最短路径优先（OSPF）协议的链路状态通告（LSA），以生成假节点。这些假节点扩大了物理拓扑，并将网络变成了虚拟网络。尽管路由器仍遵循虚拟网络中的最短路径路由，但流量会沿着物理网络中的所需路径进行控制。尽管Fibbing网络具有灵活的路由功能，但对于快速故障恢复的方法尚未进行充分的研究。通常，运行OSPF协议的IP网络在发生故障后需要花费很长时间才能收敛。IETF提出了无环替代（LFA）IP快速重路由技术，以加快故障转移速度。然而，我们发现LFA技术与Fibbing不兼容。LFA技术在Fibbing网络中的直接应用将产生流量环路。在这项工作中，我们提出了一种基于监视周期的新颖方法来快速恢复故障。通过检查监视周期的活动性，系统控制器可以迅速识别出故障的链接或故障的节点，然后执行流量重新路由。由于IP数据包转发的特性，IP网络中的监视周期必须是一个简单的周期。我们证明，任何同时具有2个顶点连接和3个边缘连接（2V3E）的网络都具有一组监视周期，可用于检测和识别任何单个链路故障。结合监视周期提供的状态模式，可以通过引入其他探测消息来检测任何单节点故障。我们提出一种算法来获取这些监视周期，并设计和实现用于网络的Fibbing控制器。为了评估所提出方法的性能，我们构建了一个物理测试平台和一个仿真网络。实验结果表明，该系统工作稳定，可以在短时间内实现快速故障转移。