OPTICAL LINK AND CONNECTOR SELECTION
Fortinet 400G and 50G Transceiver Selection Guide
Compare exact QSFP-DD, SFP56 and SFP28 order lines by reach, fiber type, connector and lane architecture before selecting an optic.
Select the optical architecture before the order line
Fortinet lists these PIDs as separate transceiver modules. Similar speed labels do not make the modules interchangeable: reach, fiber plant, connector and parallel-lane design must match both ends of the link.
| Exact PID | Rate and form | Official reach | Fiber and connector | Primary distinction |
|---|---|---|---|---|
| FN-TRAN-QSFPDD-LR4 | 400GE QSFP-DD, LR4 | 10 km | Single-mode fiber, duplex LC | Longest duplex-LC option in this group. |
| FN-TRAN-QSFPDD-FR4 | 400GE QSFP-DD, FR4 | 2 km | Single-mode fiber, duplex LC | Shorter duplex-LC 400G link than LR4. |
| FN-TRAN-QSFPDD-DR4 | 400GE QSFP-DD, DR4 | 500 m | Four-lane parallel single-mode fiber, MPO-12 | Parallel-SMF design; not a duplex-LC optic. |
| FN-TRAN-QSFPDD-DR4+ | 400GE QSFP-DD, extended DR4 family | 2 km | Four-lane parallel single-mode fiber, MPO-12 | Extends the parallel-SMF reach beyond DR4. |
| FN-TRAN-QSFPDD-SR8 | 400GE QSFP-DD, SR8 | 100 m | Eight-lane parallel multimode fiber, MPO-16 | Multimode eight-lane plant; not MPO-12. |
| FN-TRAN-SFP56-SR | 50GE SFP56, short reach | 100 m | Multimode fiber, duplex LC | 50GE host and far-end support must be confirmed. |
| FN-TRAN-SFP28-SR | 25GE / 10GE SFP28, short reach | 100 m | Multimode fiber, duplex LC | 25/10GE order line; not the 50GE SFP56 PID. |
LC, MPO-12 and MPO-16 are separate cabling decisions
FR4 and LR4 use duplex LC over single-mode fiber. DR4 and DR4+ use four-channel parallel single-mode fiber with MPO-12. SR8 uses eight-channel parallel multimode fiber with MPO-16. A matching speed alone cannot compensate for a different connector, fiber type or lane count.
- Record the installed fiber type and strand/lane architecture.
- Confirm connector gender, keying and polarity for the selected MPO plant.
- Check the far-end standard and exact optic identity.
- Verify loss budget, patch panels and total channel length.
- Keep DR4 and DR4+ as distinct reach-controlled PIDs.
Validate the exact Fortinet host and software support
The transceiver data sheet identifies the module characteristics, but procurement still requires confirmation that the intended Fortinet appliance or switch port supports the exact PID, speed and breakout mode. Record the host model, port, software release and far-end device on the quote and implementation plan.
Do not infer compatibility from the QSFP-DD, SFP56 or SFP28 form factor alone. Confirm current Fortinet documentation for the target platform and preserve that compatibility evidence with the order.
Use link evidence rather than a light-only check
Before acceptance, capture both optic identities, DOM readings where available, negotiated speed, lane or FEC state, interface errors and the tested traffic path. Investigate marginal receive power, uncorrectable errors or lane faults before the maintenance window closes.
Temperature ranges and optical parameters in the manufacturer data sheet apply to the exact order line. They do not establish the condition or authenticity of a delivered module; receiving inspection should record label, PID, serial and packaging evidence.
Exact product records
Use the PID that matches the engineered reach and connector. The plus sign in DR4+ is part of the model identity.
Official manufacturer source
This independent selection guide is not a Fortinet publication. Recheck the current transceiver data sheet and the target platform's compatibility documentation before purchase or deployment.