The 40 Gigabit Ethernet (GbE), used in today’s networks as the preferred spine uplink technology, has become commonplace in data centers. With the rise of 40GbE QSFP+ optics market, various of optics solutions are available, which offer users a lot of flexibility in connectivity. Today, I am going to summarize some 40 Gigabit fiber optic connection use cases of several types of commonly used 40GbE QSFP+ optics.
For 40GbE to 40GbE connectivity, namely the interconnection between two QSFP+ ports, users can use different optics and cables options according to different transmission distances.
- For distances of up to 7 meters: QSFP+ to QSFP+ DAC (Direct Attach Copper) cables
- For distances of up to 100 meters: QSFP+ to QSFP+ AOC (Active Optical Cable) or 40GBASE-SR4 QSFP+ transceiver with OM3 multimode fiber with MTP/MPO connectors or OM4 multimode fiber with MTP/MPO connectors (up to 150 meters)
- For distances of up to 300 meters: 40GBASE-CSR4 QSFP+ transceiver with OM3 multimode fiber with MTP/MPO connectors or OM4 multimode fiber with MTP/MPO connectors (or up to 400 meters)
- For distances of up to 1 kilometers: 40GBASE-PLRL4 QSFP+ transceiver can be used with single-mode fiber with MTP/MPO connectors
- For distances of up to 10 kilometers: 40GBASE-LR4 QSFP+ transceiver can be used with single-mode fiber with LC connectors
Tips: The standard QSFP+ MTP/MPO connector is 12-fiber connector, but use 8 out of 12 fibers.
As we know, 40GbE ports can be used either as a single port or turned into four 10GbE ports. Thus, you can use so-called QSFP+ breakout or fan-out cables with QSFP+ on one side and four SFP+ on the other side to increase the number of available 10GbE ports.
In general, according to different distance requirements, the basic three types of solutions are available:
- For distance of up to 5 meters: QSFP+ to SFP+ DAC Breakout Cables
- For distance of up to 100 meters: QSFP+ Breakout AOCs
- For distance of up to 300 meters: MTP/MPO to 4xLC Duplex OM3/OM4 multimode fiber breakout cables (mpo to lc duplex breakout cable) with the 40GBASE-CSR4 transceiver
Tips: When connect to networking switches or to server adapters which support SFP+ fiber optic connectivity, the QSFP+ DAC breakout cables are always the preferred option.
In today’s server networks, 10GbE has become commonplace. 10GbE multimode cabling with LC duplex connectors is the main infrastructure of 10GbE network. To leverage existing 10GbE cabling using LC connectors, the 40GBASE-SR QSFP+ Bi-Directional (BiDi) transceiver is an ideal choice for you. Used with WDM (Wavelength Division Multiplexing) technology, the 40GBASE-SR QSFP+ BiDi transceiver can support up to 100 meters with OM3 multimode fiber and up to 150 meters with OM4 multimode fiber cables with LC duplex connectors, allowing reuse of existing 10-Gbps fiber infrastructure for 40-Gbps connections so that helps reduce overall costs and installation time.
According to the above contents, we learned that the optics market for 40GbE connectivity is now relatively mature. Users can choose the most proper solution according to their network plan, requirements, and budget.
