Aspects of the invention are directed to service discovery in a digital broadcast network. A service discovery descriptor, which may be electronic service guide-provider and cell specific, provides mapping between a service identifier, a logical channel identifier, and a physical channel, which may be characterized by a frame identifier and a slot identifier, that is, each physical channel may have one or more slots within one or more frames. A neighboring service discovery descriptor provides mapping for the service available within neighboring cells. Aspects of the invention are directed to an encapsulation protocol that encapsulates variable length data, including, but not limited to, the service discovery descriptor and the neighboring service discovery descriptor, into fixed length data stream packets.