Arista QSFP-100G-ER-Arista | 100G QSFP28 Transceiver, Single-Mode, 40km, LC

Q: What is the difference between ER4 and ER4 Lite transceivers?
A: The ER4 Lite (sometimes labeled as ERL4 or ER4L) is a lower-cost variant that reaches 30km without FEC or up to 40km with host-enabled Forward Error Correction. Full ER4 modules may support longer distances. Both use the same LAN-WDM wavelengths and are interoperable when FEC settings match on both ends of the link.

Q: Is Forward Error Correction (FEC) required for this transceiver?
A: FEC is not strictly required but highly recommended. Without FEC, the transceiver supports approximately 30km reach. Enabling RS-FEC on the host switch extends the link distance to the full 40km specification. Ensure FEC settings are consistent on both ends of the fiber link.

Q: Which Arista platforms support this QSFP28 ER4 transceiver?
A: This transceiver is compatible with Arista switches featuring QSFP28 ports, including the 7280R3, 7500R3, and 7800R3 series. Some platforms may have thermal restrictions on certain port positions for higher-power optics. Consult the Arista Transceiver Compatibility Guide for your specific model.

Q: Can this transceiver interoperate with other vendors' equipment?
A: Yes, 100GBASE-ER4 transceivers follow IEEE 802.3ba standards and are interoperable across vendors when using single-mode fiber with matching wavelengths. Ensure both ends of the link have compatible FEC settings and meet optical power budget requirements.

Q: What type of fiber cable is required for 40km transmission?
A: This transceiver requires OS2 single-mode fiber (SMF) with duplex LC connectors. For full 40km reach, the fiber link should meet G.652 specifications with acceptable insertion loss. Calculate the optical power budget including connectors, splices, and fiber attenuation to ensure link margin.