Converged services over MPLS

As network traffic showed explosive growth in the 1990s, layer 2 services became a significant revenue source for service providers. Unfortunately, since technology development did not progress in a timely and synchronized manner, many service providers now need to manage multiple networks that are optimized for different services (voice, ATM, IP, etc.). In addition, these networks may share part of their resources in a layered manner, adding one network on top of the other one (e.g., IP over ATM), which results in overly complicated operation and inefficient use of network resources. Multiprotocol label switching provides a scalable solution for evolving service providers\´ multiple "service networks" into a unified "multiservice network." To make this transition happen, the one critical evolutionary process necessary is to carry the existing layer 1 TDM and layer 2 (ATM, frame relay, and Ethernet) traffic across MPLS core networks. This has been made possible by standardization work in the Internet Engineering Task Force (http://www.ictf.org), and has been successfully deployed by a number of service providers around the world. In this article the pre-MPLS methods of network operation for multiple services are addressed, followed by an introduction to MPLS, and the layer 1 and layer 2 over MPLS architecture is provided in detail