Transport MPLS Gets a Makeover

A new standard for MPLS-based packet transport technology is being developed by the Internet Engineering Task Force (IETF) in conjunction with the International Telecommunication Union (ITU) in an effort to create a single standard that will rival PBB-TE in the next-generation packet/optical platform domain. (See A Guide to PBT/PBB-TE.)

The seemingly cordial and unprecedented collaboration between the standards bodies is an important step for MPLS equipment vendors, as, until now, there have been parallel but conflicting developments ongoing within the two influential organizations that was likely to result in market confusion and interoperability issues down the line. That scenario would have weakened the case for MPLS as a transport technology, potentially handing an advantage to the PBB-TE camp.

Parallel developments
Until recently, the IETF and ITU were working on similar, but different, standards developments that were both focused on specifying a stripped down, connection-oriented transport version of MPLS.

The International Telecommunication Union, Standardization Sector (ITU-T) , the body that develops transport technology standards, was close to finalizing its work on the Transport MPLS, or T-MPLS, earlier this year, and had reached the stage where protocol stacks were being deployed by vendors in their transport products. The IETF, meanwhile, was working towards the same goal by extending its MPLS standard.

But while the two developments had the same aim, there were notable differences: A key potential problem with the ITU's T-MPLS is that it wasn't compatible with regular MPLS.

That problem was recognized by both standards bodies, and (amazingly) they agreed to do something about it. In April, the ITU-T's Study Group 15 noted in its newslog: "Fears that a set of next-generation network transport specifications developed by ITU-T could cause interoperability problems have been allayed. The IETF and ITU will work together to extend IETF MPLS functionality to address the needs of the transport network... The IETF and ITU-T will work jointly on the development of a transport profile for MPLS technology," to be called MPLS-TP (transport profile).

So the two organizations formed a Joint Working Team (JWT), which will, along with a number of other groups, such as the IETF's MPLS Interoperability (MEAD) team, and an ITU-T Ad Hoc MPLS group, will contribute reviews and submissions as part of the new IETF standards process.

Quick off the blocks
That process is moving faster than expected, according to Loa Andersson, chairperson of the IETF MPLS Interoperability Design (MEAD) Team and a Principal Networking Architect at Swedish R&D firm Acreo AB , who is coordinating the MPLS-TP efforts. Andersson sent the first set of documents -- "individual drafts" that will later become working group documents -- to the multiple reviewers on July 10, noting that "we are actually a bit better off than we planned."

There are nine documents for review covering a range of management and network architecture issues: See the full list here.

Andersson tells Light Reading that "after the advice that the JWT produced and was accepted by the ITU-T, most of the actual work -- writing the specifications -- has been taken over by the IETF, and is now organized by the MEAD team and involves several IETF working groups, with support from Study Groups within ITU-T."

And while the task looks daunting, the turnaround time is set to be relatively short, as the IETF and the ITU have already done a great deal of work on the details.

"MPLS-TP RFCs (standards) will start to appear during 2009, and we expect the effort will be completed during 2010," notes Andersson in an email response to questions. "The target is to produce a MPLS-TP standard that meets to goal that we all agreed to -- to be interoperable with [the] existing MPLS standard. We put huge effort into getting the right protocol design specialists, representing a good mix of telecom operators and vendors, taking active part in the development of the MPLS-TP."

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