OIF to explore Transport SDN, CFP2

The Optical Internetworking Forum (OIF) has decided to dip its toes into software-defined networking (SDN), specifically as it applies to carrier networks. The group also has launched a project that promises to shape upcoming coherent CFP2 optical transceivers, as well as a third effort that will tackle the definition of thermal interface requirements for optical modules.

May 15th, 2013

The Optical Internetworking Forum (OIF) has decided to further dip its toes into software-defined networking (SDN), specifically as it applies to carrier networks. The group also has launched a project that promises to shape upcoming coherent CFP2 optical transceivers, as well as a third effort that will tackle the definition of thermal interface requirements for optical modules.

The OIF has decided to add its two cents to the development of specifications for what has become commonly known as Transport SDN – the application of SDN principles to the carrier environment. In working with its operator members on an previously announced project (see "OIF targets 400G module, Transport SDN"), the OIF learned that there appears to be uncertainty about just what the term “SDN” means and how to define its constituent parts, according to OIF Technical Committee Chair Jonathan Sadler of Tellabs. The OIF, as a result, has decided to create an SDN Framework document that would clear up some of the mystery around SDN and help build consensus on what interface specifications might need to be created to enable Transport SDN.

The Open Networking Foundation (ONF), the most well-known of the various groups attempting to address SDN, also has a Transport SDN effort underway. Sadler says the OIF has already appointed a liaison to work with the ONF to ensure the two groups don’t step on each other’s toes. Sadler notes that some members of the OIF also work within the ONF, which should further ensure that the two groups work in a complementary fashion.

Sadler says the framework effort likely won’t tackle how SDN principles could be used to promote interaction between the IP and optical layers. However, he points to the OIF’s recently completed Multilayer Amendment Implementation Agreement as a way forward in this area. The amendment defines generic signaling and routing extensions to the OIF’s E-NNI 2.0 work. Testing has demonstrated the technology described within the implementation agreement will enable the control plane to discover the most economical way to deliver a service such as Ethernet using what an OIF press release described as “different technologies.”

Meanwhile, the Physical and Link Layer (PLL) arm of the OIF will build on its board-mounted 100-Gbps coherent transponder multisource agreement (MSA) work by tackling a coherent CFP2 transceiver. The OIF will leverage work already underway within the existing CFP MSA to “suggest” how such a module might be implemented, wrote OIF committee member Karl Gass in an email forwarded to Lightwave. Unlike larger coherent modules, the CFP2 likely will not incorporate the coherent DSP ASIC; how to interface the module with the board-mounted ASIC could prove a challenge, some module vendors have suggested (see “Acacia Communications adds funding, hints at new products”). Gass says the CFP2 project will look at this question “sort of,” in that this interface will need to be kept in mind as the project participants decide the module’s parameters.

The thermal interface project will attempt to address a longstanding lack within the communications industry: Commonality in the way heat is dissipated from a transceiver or transponder, says OIF Technical Committee Vice Chair Nathan Tracy of TE Connectivity. Each transceiver MSA tackles the problem differently, Tracy notes. The project will attempt to develop common parameters and terminology that could be applied to future MSAs.

The three new efforts come as the OIF wrapped up several projects at its quarterly meeting April 23-25 in Albuquerque, NM. In addition to the Multilayer Amendment, the group put the finishing touches on a Next Generation Interconnect Framework document. The document aims to identify areas within interconnect for 400-Gbps and 1-Tbps applications where OIF-derived specifications might prove useful. How many of these areas will become OIF targets remains an open question, although Tracy notes that work on two of the areas highlighted in the report – a 56-Gbps very short reach specification as well as another specification for chip-to-chip communication over links around 15 to 20 mm, also focused on 56 Gbps – has already begun within the OIF.

The OIF also completed a Multi-link Gearbox 2.0 implementation agreement. The agreement defines a 4x25G lane configuration that comprises 20 MLG lanes. It also defines an 8x25G lane configuration with 40 MLG lanes. Both configurations can accommodate multiple 10GBASE-R signals or a single 40GBASE-R signal for high-speed transmission designs.

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