10gbase sr is a port type for mmf multimode fiber and uses 850 nm lasers for longer reach another standard defined in ieee 8023ae is 10gbase lr10gbase lr is a port type for smf single mode fiber and uses 1310 nm lasers traditionally smf 10gbase lr sfp modules are way more expensive than mmf 10gbase lr sfp modules mmf and smf historical short range long range paradigm may change in short termsince 2014 for new installations especially indoor smf wiring is about half of mmf wiring a