MPLS-TP Camp States Its OAM Case
Some panelists on a recent Light Reading webinar explained why they don't like having a second management standard for MPLS Transport Profile (MPLS-TP), saying it messes up the goal of having a consistent MPLS layer traversing the network.
Operations, administration and management (OAM) wasn't the primary topic of "MPLS in Next-Generation Transport Networks," which took place last week and is now available in the webinar archive.
But when the topic did come up, it was clear that some companies think the International Telecommunication Union, Standardization Sector (ITU-T) shouldn't be standardizing a second OAM specification, based on the Y.1731 standard.
"The first question some service providers asked us, without knowing any debate was happening in the standard, was: 'Can you give me end-to-end MPLS-TP OAM?' If you want that to happen, you need MPLS-TP-based OAM," said Luyuan Fang, a principal engineer with Cisco Systems Inc. (Nasdaq: CSCO).
It's a continuation of the argument that began last fall, as certain vendors and carriers began calling for the Y.1731 option to be added to the standard. That added several minutes of drama to some otherwise normal standards meetings. (See Rumor: T-MPLS Group Gets Shouted Down and MPLS-TP Could Be Headed for a Split.)
The OAM options being argued about have formal names now:
- G.8113.1: Y.1731-based OAM, originally part of the T-MPLS standard and based on the recent BHH Draft submitted to the IETF. The ITU decided in February to start standardization work on this OAM version.
- G.8113.2: MPLS-based OAM that the IETF has been working on since 2009, with help from the ITU. Also known as BFD.
Now, it's worth noting that the webinar panel, consisting of representatives whose companies had paid for this appearance, did not include any supporters of Y.1731-based OAM. So, G.8113.1 had no defense as it drew criticism during the Webinar.
The primary concern, as voiced during the Webinar, is that G.8113.1 could disrupt attempts to create MPLS harmony throughout the network. The goal behind MPLS-TP was to create one transport infrastructure for services, especially newer ones, while building from a familiar technology.
"MPLS is being treated in the industry, in some cases, as a separate technology from MPLS-TP, and that's really not the case. What we're really looking for is unified MPLS," said David Sinicrope a director in the standardization development unit of Ericsson AB (Nasdaq: ERIC).
Panelists repeatedly leaned on the idea of unified MPLS, which they described as a smooth, continuous MPLS layer traversing the entire network. The idea isn't to use full-blown MPLS everywhere, but rather, to provide every network segment the option of using some form of MPLS. (Sinicrope stressed that MPLS-TP is a subset of MPLS.) "You use the profile wherever it makes sense, and you're still guaranteed to have a ubiquitous data plane and ubiquitous service that can run over all this architecture and infrastructure without jumping through hoops or having complex bottlenecks with interworking," Sinicrope said.
That MPLS would be a consistent option is important. Access networks are more sensitive to cost, for instance. In those cases, MPLS-TP in a static configuration, one that doesn't need a control plane might be a good option, panelists suggested.
"In different segments you could pick different components of MPLS," Fang said.
Fang asserted that service providers would prefer one OAM standard, but of course, that's not true of all service providers. One reason why the ITU chose to revive a Y.1731-based OAM is because of backing from service providers such as China Mobile Communications Corp. (which has already deployed the technology) and Telecom Italia (TIM) .
— Craig Matsumoto, West Coast Editor, Light Reading