SRCV: A Source Routing based Consistency Verification Mechanism in SDN

The decoupling of the control plane and data plane in software-defined network (SDN) not only promotes the innovation of network architecture but also leads to the inconsistency faults between the two layers. Through the precious works, we realize that this issue got even worse when P4, a programming language for data plane, was introduced in SDN, since many bugs and unpredictable faults may appear whether the programs are compiled or running in devices. To verify the control-data plane inconsistency in P4-based SDN, we present the design and implementation of SRCV, a source routing based control-data plane consistency verification mechanism for P4-based SDN at runtime. Firstly, SRCV generates the active probe traffic with source routing labels, and then the probe forwards along the source routing path and collects the matching flow rules information. Finally, those collected information are compared with the control plane flow rules information through symbolic execution to conduct the consistency verification. Our evaluation results show that, compared with the existing control-data plane consistency verification mechanism in P4-based SDN, the verification time of SRCV is not affected by the network topology, and only the number of switches on the checking path is linearly correlated.