Both the QSFP-DD (Quad Small Form factor Pluggable Double Density) and OSFP (Octal Small Form factor Pluggable) form factors are key in high speed, high density, low latency optical data transmission, especially for 800G technology which is becoming increasingly important in new infrastructure.
QSFP-DD transceivers are similar in design to other QSFP form factors but feature eight lanes rather than four (hence the ‘double density’) This allows them to reach higher data rates for 400G and 800G transmission with each lane operating at 50Gbps, or 100Gbps respectively.
OSFP transceivers, on the other hand, have slightly larger physical dimensions and a deeper slot insertion compared to QSFP modules. Similar to QSFP-DDs, they utilise eight lanes to achieve higher speed data transmission. The OSFP family was developed with 400G technology, meaning they currently only support two data rates – 400Gbps and 800Gbps. However, this positions them better for future developments as the industry moves toward standard speeds of 1.6Tbps and beyond.
Thermal Design & Power Management
OSFP transceivers are designed to handle higher power operations and have superior thermal capacity with their larger physical size and integrated heatsinks enabling more efficient heat dissipation. QSFP-DD modules consume less power but have less effective heat dissipation due to their smaller size.
Compatibility & Use Cases
The QSFP-DD form factor offers backward compatibility with other QSFP modules making it useful in upgrading systems that already have a QSFP based infrastructure. This backward compatibility, along with its smaller size means QSFP-DD transceivers are widely used in high density environments such as data centres.
OSFP modules are not backward compatible with QSFP transceivers due to their larger size and differing electrical interface (although an adapter can be used). This form factor is more commonly used in new infrastructure designed to support higher speeds and ensure future scalability as data speed demands grow beyond 800Gbps.
