A P4 BMv2-Based Feasibility Study on a Dynamic In-Band Control Channel for SDN.

Software Defined Networking (SDN) enables flexible and dynamic control of packet forwarding and processing by decoupling the control plane and the data plane. However, to implement an efficient and reliable in-band SDN control channel to connect controller(s) and switch/router(s), conventional static schemes such as VLAN are insufficient especially in highly utilized and/or network-topology variable wireless networks. Therefore, a dynamic in-band control channel is considered which can piggyback (embed) control messages onto data packets flowing on the network. In this paper, we report a feasibility study on the dynamic in-band control channel implemented on the BMv2 router in Programming Protocol Independent Packet Processors (P4) framework. The adverse impact on the data plane performance is experimentally investigated. It is found that the TCP goodput and packet loss characteristics are degraded as the amount of embedded information increases but the significant impact comes from not embedding/extracting the control information on data packets but sending the extracted information to a controller; which give us hints to applicable conditions and possible improvements on the dynamic in-band control channel implementation.