According to the consortium site, www.qsfp-dd.com, “QSFP-DD is a new module and cage/connector system similar to current QSFP, but with an additional row of contacts providing for an eight lane electrical interface... to enable high-speed solutions. It expands on the QSFP pluggable form factor, a widely adopted four-lane electrical interface 2×1 stacked integrated cage / connector. Cage design optimizations and module case optimizations enable thermal support of at least 7W per module. QSFP-DD electrical interfaces will employ eight lanes that operate up to 25 Gbps NRZ modulation or 50 Gbps PAM4 modulation, providing solutions up to 200 Gbps or 400 Gbps aggregate; QSFP-DD can enable up to 14.4 Tbps aggregate bandwidth in a single switch slot.”
“By quadrupling aggregate switch bandwidth while maintaining port density, QSFP-DD will support continuing growth in network bandwidth demand and datacentre traffic. Systems designed with QSFP-DD modules will be backwards compatible, allowing them to support existing QSFP modules and provide flexibility for end users and system designers.”
Molex and Cisco have announced their participation in the MSA aiming for up to 10X bandwidth to be supported on the same port. The goal is ensuring mechanical, electrical, thermal and signal-integrity interoperability for module components produced by different manufacturers. Members of the MSA are developing operating parameters, signal transmission speed goals, and protocols for QSFP-DD... with a cear path to future 2x100 GbE and 400 GbE interfaces. By maintaining the same port density per rack unit, customers can speed up networks without redesigning the architecture.