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 Tuesday, 16 October 2007

Experts from the standardization sector of ITU (ITU-T) and the Internet Engineering Task Force (IETF) have agreed to recommend progression of Transport-MPLS (T-MPLS) standards work in a way that ensures compatibility, consistency, and coherence of MPLS technology when used in transport networks. The recommended approach, which recognizes and leverages ITU-T and IETF design expertise and authority, is expected to resolve concerns raised regarding usage of common Ethertypes for IETF MPLS and T-MPLS when running over an Ethernet backbone. Broader review and approval of the proposal by the two standards bodies is expected in the coming months.

The experts proposed in a joint statement that "The IETF and ITU-T will work in close collaboration on T-MPLS" and that "a joint working team of experts from the IETF and ITU-T be established to propose how to progress the various aspects of the requirements, solutions, and architecture for the T-MPLS work." The initial goal of the working team will be to examine T-MPLS work, and foster "an agreement on leadership roles and the modifications necessary to develop an architecture that it is compatible, coherent and consistent between both transport and IETF MPLS technologies."

Yoichi Maeda, Chairman of ITU-T's Study Group 15, home of the T-MPLS work said: "This type of agreement is a characteristic of the spirit of cooperation that exists between ITU-T and IETF. Both organizations understand that in order to meet the needs of industry it's imperative to quickly resolve differences and avoid duplication of work."

"Future work," the proposal states, "will be progressed by first analyzing the requirements and desired functionality." Since T-MPLS utilizes MPLS functionality extensively, the experts recommend that, "The IETF Standards Process will be used for extensions or modifications of IETF MPLS Technology." It was clearly noted that there are aspects of the problem space that lie outside the domain of expertise in the IETF or straddle both organizations, e.g., management of transport equipment, and some aspects of OAM and survivability. The working team will be tasked to help identify which of these aspects are best standardized in IETF RFCs and which in ITU-T Recommendations.

T-MPLS has been under development for three years in ITU-T with four specifications published, including an architecture document, a network-to-network interface (NNI), an equipment specification and a protection switching document. T-MPLS draws extensively on IETF MPLS, a foundation of more than 50 RFCs published by the IETF MPLS and PWE3 Working Groups over the last eight years.