The Quad Small Form Factor Pluggable Double Density (QSFP-DD) Multi Source Agreement (MSA) group has released a pair of updated specifications for the high-speed pluggable transceiver form factor. Version 4.0 of the hardware specification includes additions to the thermal section, synchronous clocking, and improved keying. Version 3.0 of the Common Management Interface Specification (CMIS) offers a set of management interactions and a register map for 8- and 16-lane optical modules.
The MSA QSFP-DD hardware specification defines a form factor that supports up to 400 Gbps in aggregate over an 8x50-Gbps electrical interface. The CMIS supports multiple interface settings and speed negotiation controls. It enables support for multiple “data paths” where each data path comprises a sub-group of lanes to be controlled together within the multi-lane module. The MSA group says that it has collaborated on the CMIS with other industry standards groups after getting the ball rolling itself. The group describes the CMIS as the first management specification designed to address a wide range of module form factors, functions, and applications, from passive copper cable assemblies to coherent DWDM modules.
The CMIS defines the host-to-module interactions that ensure that modules will initialize and operate consistently through the management interface. The defined state machines simplify operation by enabling the host to identify and control the power-up sequencing of new high-power class modules, says the group. It is similar to the QSFP module management interface specification, with expansion to the management of 8 and 16 lanes using a “banking” feature.
“Through strategic collaborations we are able to provide specifications that address the challenges of common management requirements for the mechanical, thermal, and electrical parameters,” said Tom Palkert, editor of the QSFP-DD MSA specifications. “The CMIS breaks the barriers to multi-vendor interoperability by addressing the ability of next-generation modules to meet user needs.”
Launched in March 2016 with the goal of developing a form factor in the QSFP family that would accommodate 200 and 400 Gbps requirements, the QSFP-DD MSA group includes founder-promoters Broadcom, Cisco, Corning, Finisar, Foxconn Interconnect Technology, Huawei, Intel, Juniper Networks, Lumentum, Luxtera, Mellanox Technologies, Molex, Oclaro, and TE Connectivity. More than 50 other companies are contributors. It released its first hardware specifications a year later (see "QSFP-DD MSA Group releases optical transceiver form factor specification").
The QSFP-DD announcement is the third this week that describes new MSA transceiver specifications (see also “SFP-DD MSA releases version 2.0 of interface specification” and “400G BiDi MSA Group releases first multimode fiber optical transceiver specification”). With ECOC next week in Rome, Italy, members of all three MSAs are expected to discuss their activities on the show floor.
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