Features and Benefits of QSFP-DD

QSFP-DD expands on the QSFP pluggable form factor, a widely adopted four-lane electrical interface.

QSFP-DD is with 2x1 stacked integrated cage/connector. Due to industry need, most pluggable form factors eventually see developed a two-high stacked cage-connector system in addition to a one-high cage connector system. Often the one-high system is included in the initial MSA specification and the two-high is left to independent individual suppliers. To serve better the industry, the QSFP-DD MSA Group chose to develop concurrently both the one-high and the two-high cage-connector systems.

SMT connector and 1xN cage, Cage design optimizations and module case optimizations enable thermal support of at least 12W per module. The QSFP-DD Specification defines power classes up to 14W as well as a >14W class. Due to innovative thermal management techniques used in the module and cage designs, QSFP-DD modules support power levels of at least 12W in a typical system design. The extensive knowledge and experience of system design with QSFP family form factors enables innovative systems solutions that could extend beyond that range. Thermal management features needed for the higher power consumption classes are relaxed for the lower power classes to avoid unnecessary costs.

QSFP-DD electrical interfaces employs eight lanes that operate up to 25Gb/s NRZ modulation or 50Gb/s PAM4 modulation, providing solutions up to 200Gb/s or 400Gb/s aggregate. QSFP-DD can enable up to 14.4Tb/s aggregate bandwidth in a single switch slot. By quadrupling aggregate switch bandwidth while maintaining port density, QSFP-DD can support continuing growth in network bandwidth demand and datacenter traffic.

Before the emergence of QSFP-DD, the most popular interfaces in the networking industry consisted of single (SFP/SFP+) or quad lanes (QSFP+/QSFP28). However, to accommodate expected demand for data bandwidth or channel capacity, eight lane interfaces are being defined in venues such as Ethernet. The currently available form factors that support eight lane interfaces do not have all the desired features or density necessary to support the next generation systems that plan to implement these higher rate interfaces. Thus, the QSFP-DD MSA group extended and defined QSFP-DD based on QSFP (QSFP+/QSFP28).