Voice Transport Techniques over MPLS

In this paper, we discuss currently evolving technologies for packet based real-time voice communication. Packet based voice has gained popularity in the toll-quality market due to its flexibility and cost effectiveness. IMS (IP Multimedia Subsystem) is being developed for converged voice and data services. While initially it was intended for mobile networks, it has been expanded to include support for fixed networks. In the wired network, the quality of service needed for media traffic can be provided by MPLS and related protocols. The traffic engineering and quality of service mechanisms of MPLS and Diffserv allow the differential treatment of premium traffic on predefined LSPs (Label Switched Path). Recently T-MPLS has been introduced as the transport network for connection oriented packet switched traffic, dropping some of the MPLS features that were irrelevant for connection oriented applications. We introduce IMS and then look at implementation agreements, methods and protocols for transport of voice over MPLS (multi protocol label switching) networks.