1. A method comprising: configuring a circuit emulation service (CES) over an internet protocol (IP) network based on properties of the IP network, the CES being configured from a local interworking function to a remote interworking function; encapsulating data received at a constant bit rate at the local interworking function into a plurality of IP packets configured according to the CES; and transporting the IP packets from the local interworking function to the remote interworking function according to the CES.