It differs from these paradigms because OBS control information is sent separately in a reserved optical channel and in advance of the data payload.
These control signals can then be processed electronically to allow the timely setup of an optical light path to transport the soon-to-arrive payload.
OBS provides more bandwidth flexibility than wavelength routing but requires faster switching and control technology.
The control signal is transmitted in optical form in a separated wavelength termed the control channel, but signaled out of band and processed electronically at each OBS router, whereas the data burst is transmitted in all optical form from one end to the other end of the network.
If the data transmission duration is short relative to the set up time, bandwidth may not be efficiently utilized in the OCS system.
In comparison, OBS does not require end-to-end lightpath set up, and therefore may offer more efficient bandwidth utilization compared to an OCS system.
If the guardband is large relative to the average packet or burst size, then it can limit data channel throughput.