https://community.fs.com/blog/do-you-know-all-these-terminologies-of-wdm-technology.html
...
SR4 uses a single wavelength 4 pairs of fibres, whereas the BXSR uses a 4 wavelengths over a single pair of fibres.
BXSR
https://apps.juniper.net/hct/model/?component=JNP-QSFP-100G-BXSR&prd=QFX5110&cat=Transceivers
LC duplex Multimode fiber
Vs 100G SR4
https://apps.juniper.net/hct/model/?component=JNP-QSFP-100G-SR4
12-ribbon multimode fiber crossover cable with female MPO/UPC connectors
