The WAN consists of network and security stacks, both of which have gone through several phases of evolution. Initially, we began with the router, introduced WAN optimization, and then edge SD-WAN. From the perspective of security, we have a number of firewall generations that lead to network security-as-a-service. In today’s scenario, we have advanced to another stage that is more suited to today’s environment. This stage is the convergence of network and security in the cloud.