The Overlay Management Protocol is the Cisco SD-WAN control protocol used to exchange routing, policy, and management information among Cisco SD-WAN devices, as described in Overlay Routing Overview. https://www.cisco.com/c/en/us/td/docs/routers/sdwan/configuration/security/vedge/security- book/security- overview.html#:~:text=The%20Overlay%20Management%20Protocol%20is,described%20in%20 Overlay%20Routing%20Overview.