MPLS proposal spawns IETF, ITU turf war

The IETF and ITU standards bodies are sparring over a set of MPLS specifications that some say could lead to massive interoperability issues for service providers if left unchanged.

The Internet Engineering Task Force (IETF) is at odds with the International Telecommunication Union (ITU) over a special transport network architecture the ITU’s Telecommunication Standardization Sector (ITU-T) is developing to allow Multiprotocol Label Switching (MPLS) traffic to run over an Ethernet backbone. Among the network equipment vendors that have been contributing to the development are Alcatel-Lucent, Ericsson, Fujitsu and Tellabs.

The problem, according to the IETF, is that the ITU’s Transport-MPLS (T-MPLS) specification will not work with the billions of dollars in routers and switches that carriers have installed in recent years based on the IETF’s MPLS standards.

"The situation is catastrophic," says Stewart Bryant, IETF liaison to the ITU-T on MPLS issues and a technical leader at Cisco. "There’s a fundamental opportunity for a major train wreck" between the IETF's MPLS and the ITU-T’s T-MPLS.

Bryant says the problem is that T-MPLS uses the same EtherType as MPLS, which will lead to confusion in operational networks. An EtherType is a field in the Ethernet network standard that indicates which protocol is being transported.

"If you think about a piece of network equipment, it looks at the EtherType and that tells it how to process the packet. The EtherType is the same for MPLS and T-MPLS, so we are extremely unhappy about that. T-MPLS should use a different EtherType, ideally called T-MPLS so there is absolutely zero confusion in dealing with T-MPLS or MPLS traffic," Bryant explains.

"Our concern is that there should be absolutely nothing designed, implemented or specified that risks the deployed base of MPLS equipment," Bryant adds.