分段路由(segment routing,SR)是近几年IETF提出的一种路由机制,其目的是使IP/MPLS网络面向服务并且更高效。SR减少现有MPLS网络控制平面复杂的协议(LDP/RSVP-TE),并实现流量工程等机制。与基于RSVP的显式路径中隧道中间节点维护报文流的状态不同,基于SR的显式路径只在入口边界路由器中维护报文流的状态,从而提高了网络的可扩展性,因此SR对于下一代互联网具有重要的研究意义。对SR的实现机制进行了研究,利用软件路由平台Click,对基于PCE架构的SR控制平面子系统和基于MPLS的SR数据平面子系统的各个模块进行实现,并在实际中进行部署,以验证SR软件路由器的可行性。
Segment routing (SR) is a routing mechanism proposed by IETF in recent years, which aims to make the IP/MPLS network service-oriented and more efficient. SR eliminates the complex control plane protocol (LDP/ RSVP-TE) of the MPLS network, while SR implements the traffic engineering mechanism. Different from the explicit path in the RSVP tunnel which maintains the state of each flow in the middle of the tunnel, the explicit path based on SR only maintains the state of flow at the entrance border router of the SR domain. For this reason, SR improves the scalability of the network. Therefore the research of the SR mechanism is very important to the next generation internet. The realization mechanism of SR was studied, using the click router. The SR control plane subsystem based on PCE architecture and each module of MPLS-based SR data plane subsystem were implemented and deployed in practice to verify the feasibility of the software router in actual deployment.