SAN software components can form a complex set of functions. SAN configurations, given their multicomponent assembly, require software that provides the distributed communications capabilities of the fabric, as well as the core -level functionality that drives the internal routing and linking of FC frame processing. The bottom line to all this is that SAN software supporting a new infrastructure (for example, a Fibre Channel storage network) is much more complex than NAS environments. Additional discussions regarding these differences in terms of applicability can be found in Chapters 17, 18, and 19.
Many SAN software functions are accessed outside the switch operating system, which makes the configuration more complex as processing takes place both externally (out-of-band) and internally (in- band ). The switch, although similar to the internal RTOS in NAS solutions, is not accessible except through the configuration process. Configuration complexities require that some training be made available prior to the design and implementation of the SAN software.