Interprovider IP-MPLS services: requirements, implementations, and challenges

With the worldwide success of IP-MPLS [E. Rosen et al., Jan. 2001] networks deployment, inter-connecting multiple provider IP-MPLS networks for global reachability becomes the next important step. Many providers have implemented MPLS interprovider connections. In this article we first briefly describe the drivers behind the need of interprovider IP-MPLS services, such as layer 3 VPNs [E. Rosen and Y. Rekhter, Oct 2004], pseudowire emulation for transporting layer 2 traffic over IP-MPLS, VoIP, and others. We then discuss the general requirements for the interconnections, from end users´ and service providers´ perspectives, including security, scalability, manageability, QoS, and end-to-end SLAs. We then address the deployment options and challenges faced by service providers. Specifically, we discuss the following areas of interprovider service implementation: protocol implementation options for L3 VPN and their trade-offs, methods for guaranteeing consistent QoS across providers´ boundaries, interprovider traffic engineering approaches, and operation challenges: from business to processes, from troubleshooting/monitoring to SLAs. By identifying the issues and challenges, our ultimate goal is to move toward the development of much needed common practices and procedures to assist in the establishment of interprovider IP-MPLS services.