The Australian Square Kilometre Array Pathfinder (ASKAP) is an array of 36-antennas located in Western Australia. Each antenna is outfitted with a 192-port phased array feeds (PAF) which targets wide field of view radio astronomy. Both PAFs and Correlators require backplanes to cross connect data inputs; in the case of a PAF its 192-ports into the Beamformer, and then for the Correlator its 36-antenna inputs. For ASKAP these digital cross connect communications require approximately 300Tbps - the aim is to do this as efficiently as possible (power, cabling, RFI and programming.). This paper explores existing solutions and also describes advancements in the second generation ASKAP hardware using optical backplane technology. These technology steps will become critical for SKA which will consist of many orders of magnitude more antennas than ASKAP, and may also potentially use PAF technology.