StarTech.com Cisco QSFP-40G-LR4-S Compatible QSFP+ Transceiver Module - 40GBASE-LR4~Cisco QSFP-40G-LR4-S Compatible QSFP+ Module - 40GBASE-LR4 - 40GbE Single Mode Fiber SMF Optic Transceiver - 40GE Gigabit Ethernet QSFP+ - LC 10km - 1270nm to 1330nm - DDM Cisco Firepower, ASR1000, ASR9000

Product Overview

AI-generated summary

At ~£747 ex-VAT for a 10km 40GbE QSFP+ LR4 optic, this is one of those “works perfectly… if you’re in the right design” purchases. The big win is operational simplicity: if your switch/router optics are picky and this specific StarTech/Cisco-compatible line is known to behave, you avoid the classic headaches around vendor locking and flaky optics. It’s also a sensible choice for customers running single-mode SMF at medium distances where 40G doesn’t need to go far (think campus, data hall to data hall, or back-to-core links).

Who should buy: teams standardising on Cisco-style optics for Cisco Firepower/ASR gear and who value predictable plug-and-play behaviour over saving a few quid with unknown generics. Who should *not* buy: anyone not fully confident it’ll be accepted by their exact chassis/firmware combination, or anyone expecting “any LR4 will work” logic—optics compatibility is where budgets go to die. If you’re only replacing one port and uptime matters, this price is tolerable for the reduced risk. If you’re buying in bulk and can validate compatibility across your fleet first, it can be good value. If you can’t, I’d rather you pay for testing/verification than gamble at £747 a pop.