The Quad Small Form Factor Pluggable Double Density (QSFP-DD) MSA Group (Multi Source Agreement Group) announced the release of an updated 4.0 Hardware specification for the QSFP-DD form factor at September 18, 2018. The latest hardware specification to address the industry need for an improved high-density, high-speed networking solution. Other notable features to the updated 4.0 hardware specification include the release of the 3.0 CMIS (Common Management Interface Specification) which provides a set of management interactions and a register map for 8 and 16 lane modules.
The initial work on the CMIS was done by the QSFP-DD MSA and was later expanded to include other industry standards groups. The CMIS is similar to the QSFP module management interface specification with expansion to the management of 8 and 16 lanes using a ‘banking’ feature. The CMIS is the first management specification designed with the intent to cover a wide range of module form factors, functionalities and applications, ranging from passive copper cable assemblies to coherent DWDM modules.
The CMIS defines the host-to-module interactions needed to ensure that modules will initialize and operate consistently through the management interface. The defined state machines simplify operation by allowing the host to identify and control the power up sequencing of new high-power class modules.
“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.”
The MSA QSFP-DD HW Specification supports up to 400 Gbps in aggregate over an 8 x 50 Gbps electrical interface. The CMIS supports multiple interface settings and speed negotiation controls and allows support for multiple “Data Paths” where each “Data Path” consists of a sub-group of lanes to be controlled together within the multi-lane module.
The latest QSFP-DD MSA specifications are available for free download at the QSFP-DD MSA website: www.qsfp-dd.com.
