1. A method comprising: receiving a first Internet protocol (IP) flow for an IP session for a subscriber; selecting a first service function group from a plurality of service function groups to perform one or more services for the IP session for the subscriber, wherein each of the plurality of service function groups comprises a plurality of service function chain types and wherein each service function chain type comprises an ordered combination of one or more service functions; assigning the IP session for the subscriber to the first service function group; and forwarding the first IP flow for the IP session of the subscriber across a first service function chain type for the first service function group based, at least in part, on a service policy for the subscriber.