Introduction: New technologies are replacing the onboard space networks based on bus topologies. One of these technologies is SpaceWire. New communication protocols are being developed, expanding SpaceWire functionality. The protocol developers should provide all the required technical characteristics for data transmission and processing. Purpose: Analysis of the existing requirements for communication protocols, and development of consolidated set of requirements that will take into account the modern requests of the space industry. Results: The analysis of the existing demands on communication protocols resulted in a set of consolidated requirements for the physical-network layers’ protocols and the transport layer protocols. The requirements cover the speed, latencies, transmission distance, transmitted information amount, fault detection functionality, time synchronization between the devices, quality of service, main user data types, and data transfer modes at the transport level. The existing SpaceWire protocols are defined as a special class of protocols, possessing unique characteristics. Practical relevance: The performed analysis can simplify the implementation of new onboard communication protocols and provide a required level of technique for new generation spacecraft.