Packets are encapsulated and sent from a service node to an application node for applying one or more Layer-4 to Layer-7 services to the packets, with service-applied packets being returned to the service node. An identification of a virtual private network (VPN) may be carried within a request packet, encapsulating a particular packet, sent by a service node to an application node for applying a service to the particular packet; with the corresponding response packet sent to the service node including an identification of the VPN for use by the service node in forwarding the services-applied packet. Additionally, parameters may be included in a request packet to identify a particular service of a general service to be applied to a particular packet encapsulated in the request packet.