SFP Modules: SFP can be regarded as new generation version of the GBIC. SFP is short for Small Form-factor Pluggable. SFP modules utilize the smaller LC type of fiber interface and the main body size of SFP is only about half of GBIC. Signal transmission rate of these modules range from 100Mbps up to 4+Gbps, transmission range can be from 500 meters to 120+ kilometers. SFP modules are available with operating optical wavelengths of 850nm, 1310nm and 1550nm, as well as CWDM and DWDM wavelengths. Like GBICs, SFP modules are also hot pluggable, this make them easy to change and easy for maintenance compared with traditional board level optical interface modules.