This paper concerns with the main considerations for designing the Inter Satellite Link (ISL) for the system of IiNUSAT. It starts with the assessment of microwave spectrums required for operating the RF antennas and transceivers. In particular an analysis of how to cope with Doppler effects which inherently present in LEO system is presented. The result will require a certain wide bandwidth of the PLL if we are to operate a coherent communication system. Furthermore one should attempt to a finer phase synchronization effort. Finally a choice of IEEE 802.11 is proposed for the networking of the group of satellites.