A method and system to rout a Voice over Internet Protocol (VoIP) call based on a service class of a subscriber enables efficient utilization of bandwidth by providing service corresponding to the subscriber service class, while enabling use of a Virtual Private Network (VPN) which provides security to a VoIP service. The method includes: determining a service class of a subscriber upon packet data being received from the subscriber; determining whether the received current packet is packet data to be routed over an encrypted network or a non-encrypted network, based on the service class of the subscriber; encrypting the received packet data with an encryption processor and then routing the encrypted packet data to a final destination with a router upon a determination that the received packet data is to be routed over the encrypted network; and directly routing the received packet data to the final destination with the router without encrypting the received packet data upon a determination that the received packet data is to be routed over the non-encrypted network without being encrypted.