The current specification of the Segment Routing (SR) architecture requiresenhancements to the intra-domain routing protocols (e.g. OSPF and IS-IS) sothat the nodes can advertise the Segment Identifiers (SIDs). We propose asimpler solution called PMSR (Poor Man's Segment Routing), that does notrequire any enhancement to routing protocol. We compare the procedures of PMSRwith traditional SR, showing that PMSR can reduce the operation and managementcomplexity. We analyze the set of use cases in the current SR drafts and weclaim that PMSR can support the large majority of them. Thanks to the drasticsimplification of the Control Plane, we have been able to develop an OpenSource prototype of PMSR. In the second part of the paper, we consider aTraffic Engineering use case, starting from a traditional flow assignmentoptimization problem which allocates hop-by-hop paths to flows. We propose a SRpath assignment algorithm and prove that it is optimal with respect to thenumber of segments allocated to a flow.
展开▼
