@ajayshenoypadavu
Browser is an application working in a client server topology where your blowser will act as client and the cisco server will act as server. The cisco server is listenning on port 80 or 443 and your blowser will stablish a connection to that server in one of these two ports. This is how you reach the cisco server.
The DNS is something apart from the client server connection and happens before the client server connection. When your browser need to communicate with cisco.com, it will first use the DNS to resolve cisco.com into an IP address and then send the connection to the IP address.
