Considering QSFP-40G-SR4-S — any real world insight before I order?

[robertanderson]

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I’m about to order a few QSFP-40G-SR4-S modules for some short 40G links inside our data center and want to hear from people who have actually deployed them. We already have multimode MPO fiber in place, so these seem like the logical choice to avoid rewiring or pulling new cabling.

Before I click “buy,” a couple of questions I’d love real feedback on:

1. Plug and play vs troubleshooting: Have your QSFP-40G-SR4-S links come up cleanly on the first try once the MPO was connected and cleaned, or did you spend time checking polarity and patch configuration before things lit up?
2. Vendor/platform quirks: Any switch models or firmware versions that treated QSFP-40G-SR4-S differently? I’ve heard sometimes optics behave oddly until the right code or settings are applied.
3. Long term stability: Once in production, do these stay stable under constant load, or have you found yourself revisiting them after a few weeks/months because of intermittent issues?

I want these to be a reliable solution for short 40G links rather than something that needs constant babysitting. If you’ve bought and deployed QSFP-40G-SR4-S recently, what would you double check before ordering? And how has your experience been weeks or months after installation? Appreciate the real world perspective!