Frequently Asked Questions
- Q: What will the microQSFP (Micro Quad Small-Form-Factor Pluggable) MSA address and the microQSFP specification define? (Optical interfaces and copper?)
- A: The microQSFP MSA will develop a specification for a new compact module form factor, microQSFP, and make the specification available to the industry to promote industry adoption of compatible products that can be used for a variety of applications including copper cable and fiber-optics transceivers in a manner similar to SFP or QSFP form factors. There will be sufficient details in the specification such that the components of the form factor (host board electrical edge connector, cage and plug with latching mechanism, where the plug can be a cable termination or transceiver) are mechanically and electrically interchangeable if compliant to the specification.
The microQSFP specification is expected to be applied to direct attach cables (DACs), active optical cables (AOCs), and connectorized optical modules to enable higher port density. The microQSFP module’s compact design will be well suited for a wide range of applications within the data center accommodating copper, VCSEL (vertical cavity surface emitting laser), SM (single mode) laser or Silicon Photonics (SiP) based technology.
- Q: Aren’t smaller modules limited by thermal constraints?
- A: microQSFP modules will have enhanced thermal management capabilities and therefore will be well suited for higher power applications that extend links outside of the data center. Initially, microQSFP modules will support links similar to SFP and QSFP and as technology improves and the relative power decreases, longer reach applications up to 100’s of km may be possible.
- Q: Why now? What is driving this development?
- A: There are a number of factors driving the formation of the microQSFP MSA. First, there is always interest in improving port density and signal rate. Although QSFP28 can support 3.2Tb/s switches, there was little the QSFP form factor could do to support the next generation 4.8 and 6.4 Tb/s switches, therefore the MSA founders felt it was critical to develop a smaller form factor to support the next generation switches now. Then, there is the development of the OIF's CEI-28G VSR electrical interface, the IEEE's 802.3bm and 802.3by optical interfaces and the establishment of the 25G/50G Consortium, enabling easy re-use of existing electrical and optical link definitions that can support a wide range of solutions such as 4x10G, 2x25G, 4x25G, etc. As end users and equipment developers strive to keep up with higher port density and aggregate bandwidth, the key missing hardware is the definition of a higher density electrical connector and enhanced thermal performance module form factor. Similar trends/needs exist in other industry standards.
- Q: Is this a form factor for client-side interfaces or line-side (long distance) interfaces?
- A: The microQSFP MSA specification will define a high-density, pluggable, 4-channel form factor that supports signaling up to 28 GBaud and beyond. Either direct attach cables or optical transceivers can be implemented. Given the high-density of the microQSFP module, it is less likely to be used for long-haul line-side applications although it may happen with time. The most likely applications will be client-side interfaces inside the data center that support up to 10 km on SMF (single mode fiber) and 100 meters on MMF (multi-mode fiber).
- Q: How does the port density of microQSFP compare with present 4x28G QSFP or 1x28G SFP density?
- A: The microQSFP form factor will be approximately the same width as the SFP form factor, but the electrical connector will provide four electrical channels like the QSFP form factor. In a two row implementation, the microQSFP will fit at least 48 ports on a line card and, in a three row implementation, at least 72 ports can be accommodated. When each lane is used as an independent channel, it allows microQSFP to offer 4x the port density of SFP and, when used in an aggregated lane mode, to offer 1.5x the port density of QSFP.
- Q: Is the microQSFP MSA reliant on other outside standards activity?
- A: This work is independent of other standard activities. The current data center demands higher aggregate bandwidth and lower latency interfaces. The microQSFP MSA is formed to develop a high density interface using existing technology based on 25G per channel to meet the current demand. This work can be used by other standards if they choose.
- Q: Is there a roadmap planned for the microQSFP MSA?
- A: The microQSFP MSA group is defining the microQSFP module for 3.5+W operation and 28Gb/s per channel. It is expected that this will also support 50Gb/s requirements as well. As technologies evolve, reasonably higher signal rates and thermal upgrades can be expected.
- Q: Where can I download the MSA's new Rev 2.4 Specification?