System for transporting a sub-rate data stream over a communication network using a selected network protocol. The sub-rate data stream has an associated sub-rate protocol. The system includes a rate adapter to receive the sub-rate data stream and adapt a rate characteristic asso=iated with the sub-rate protocol to a rate characteristic associated with the selected network protocol to generate a rate-adapted data stream. The system also includes a payload framer to receive the rate-adapted data stream and frame the rate-adapted data stream into a payload for transmission over the communication network using the selected network protocol.