or SI - A system integrator brings together multiple pieces of a complex system like a municpal broadband network, in much the same way that a general contractor takes responsibillity to get a house built. The SI serves a vital role as a single point of contact responsible for the creation of the system. Examples of an SI include IBM Global Services, which works with several vendors on a custom solution, and WFI, which started off building cellular networks and migrated to building municipal networks.