Does anyone know what's the difference between LR1 and LR4 optics?
asked Feb 11, 2021 at 19:11
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Removed the off-topic request for resources.– Ron Maupin ♦Commented Feb 11, 2021 at 19:24
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Did any answer help you? if so, you should accept the answer so that the question does not keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer.– Ron Maupin ♦Commented Dec 23, 2021 at 16:35
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1 Answer
As in 10GBASE-LR versus 40GBASE-LR4?
-L stands for long ~1300 nm wavelength (as opposed to -S for 850 nm and -E for ~1550 nm). -R stands for large block code 64b/66b.
The suffix 4 stands for the number of lanes. With -L, those lanes are multiple wavelengths (CWDM) that are merged by the sender and split again by the receiver. Accordingly, 40GBASE-X requires a QSFP+ optical module with four (Q) 10 Gbit/s (SFP+) lanes. 10GBASE-X uses a narrower, single-lane SFP+ module.
There are other module form factors than (Q)SFP(+) but those are the ones most widely used. The lane scheme applies to all of them since it is required by the PHY standards.
