FN-TRAN-QSFP+SR-BCC | Fortinet Compatible 40GB Multi-Mode 150m (40GBASE-SR4)

Q: Will this work in place of the Fortinet FN-TRAN-QSFP+SR?
A: Yes. This transceiver is engineered to the same IEEE 802.3ba 40GBASE-SR4 standard, uses the same QSFP+ form factor with MPO-12 connector, operates at the same 850nm wavelength, and delivers the same 40 Gbps data rate over multi-mode fibre. It is plug-and-play compatible and functions identically to the Fortinet original in systems with QSFP+ or QSFP28 slots.

Q: Which Fortinet platforms support this transceiver?
A: This transceiver works in any Fortinet system with QSFP+ or QSFP28 slots, as confirmed by the official Fortinet datasheet. Compatibility is determined by the physical slot type and IEEE 802.3ba support in the platform, not by specific model numbers. If your Fortinet device has a QSFP+ or QSFP28 port and supports 40 Gigabit Ethernet, this transceiver will operate correctly.

Q: What fibre type and reach does this transceiver support?
A: This is a multi-mode transceiver optimised for OM3 and OM4 fibre. It reaches 100 metres over OM3 fibre and 150 metres over OM4 fibre. The four parallel lanes at 850nm use VCSEL technology designed for laser-optimised multi-mode fibre only. Do not use this transceiver with single-mode fibre, as the wavelength, connector type, and power budget are incompatible.

Q: How does the four-lane architecture of 40GBASE-SR4 work?
A: 40GBASE-SR4 splits the 40 Gbps signal into four independent 10.3125 Gbps optical lanes, transmitted simultaneously over a 12-strand MPO ribbon cable (eight active fibres, four Tx and four Rx). Each lane uses 64B/66B encoding and an 850nm VCSEL transmitter. This parallel architecture avoids the complexity and cost of a single 40 Gbps serial lane, enables use of proven 10G-class optics, and permits 4x10G breakout applications when needed.

Q: Does this transceiver support Digital Diagnostic Monitoring and what parameters can I monitor?
A: Yes. This transceiver provides full DDM/DOM functionality per the QSFP+ MSA specification, accessible via the I2C interface. You can monitor per-channel transmitted and received optical power, module internal temperature, laser bias current for each of the four VCSEL channels, and supply voltage. Most network management systems with SNMP support can poll these parameters in real time for link health assessment and early fault detection.