The QSFP-DD MSA Group Has Announced New Specifications and a Whitepaper.

The Quad Small Form Factor Pluggable Double Density (QSFPDD) Multi-Source Agreement (MSA) group has announced the release of hardware standard revision 6.0, which updates QSFP-DD while also adding QSFP-DD800 and QSFP112. The specification is available at

QSFP-DD is the industry’s most popular 8-lane data center pluggable module form factor. Systems created for QSFP-DD modules can be backward compatible with existing QSFP form factors, giving end-users, network platform designers, and integrators complete flexibility. This 7th public release adds QSFP-DD800 and QSFP112 Mechanical and Board Definitions and supports 100 Gb/s electrical host interfaces. It also includes electrical and management timing for QSFP112 modules. Revision 6.0 features revised power supply test techniques and support for a module power rating of up to 25 W. The power contact rating of the module has been enhanced from 1 A to 1.5 A. There is also an appendix providing normative connection performance data.

In addition, the group announced the availability of an updated Common Management Interface Specification (CMIS) revision 5.0 for QSFP-DD, QSFP-DD800, and QSFP112. The CMIS specifies the host-to-module interactions required to ensure that modules start-up and run consistently. This release includes various expansions and a thorough technical and editorial consolidation. It is consistent with the timing specifications stated in the previously released QSFP-DD MSA HW Spec revision 5.1 and current revision 6.0. CMIS is widely used in the industry and is not limited to the QSFP/QSFP-DD module family. Many implementers’ feedback has also been consolidated to enhance and extend the standard.

“It’s great to see how the 63 firms engaged collaborated to unify these critical QSFP/QSFP-DD form factors and software to future-proof data centers while keeping backward compatibility,” said Scott Sommers, founding member and MSA co-chair.

The MSA group also announces the publication of a new whitepaper on thermal management. In high-performance network systems, pluggable optical modules must be efficiently cooled. This is especially true for the new high power 25 W modules for QSFP-DD800 systems, which must adequately dissipate heat to maintain operational performance. For QSFP-DD modules, careful thermal design of the module, cage, heatsink, and the overall system is essential for effective heat dissipation. This new whitepaper describes approaches for achieving this aim in QSFP-DD/QSFP-DD800 module design and QSFP-DD/QSFP-DD800 system architecture. It includes experiments and simulated studies to illustrate the effectiveness of various strategies.

“The performance and power needs for high-speed network systems are always growing,” said MSA co-chair Mark Nowell, a founding member. “This whitepaper captured the design experience gained by many companies over the last few years and was written to help design engineers understand how they can achieve the thermal characteristics their system requires, even when using new 25 W modules, ensuring the reliable operation of their products.”