What are the requirements of heirarchy in communication in CAN protocol?

There are four main requirements of hierarchical networks are:
01. Deterministic behavior – A system exhibits a deterministic behavior when the performance measures of its services are predictable under a number of conditions. For in-vehicle networks, perhaps the most important performance measure is message latency. Message latency is defined as the time interval from when a transmitter node enqueues a message for transmission (i.e., a transmission request) until such a message is successfully read (i.e., a reception) by a receiver node.
 
02. High speed – High speed is relative, in the future up to 100Mbs might be required for the backbone, to support global system integration including transfers of large amounts of information. 1 Mbps for subnetworks with milliseconds range, few bytes long, monitoring and control transactions.
 
03. Flexibility – Flexibility is also difficult to define and characterize precisely due to its many contexts, meanings, and interpretations. Flexibility is addressed to all levels including the architecture, implementation, and service levels.
 
04. Dependability – Dependability involves reliability, availability, maintainability, safety, integrity, and confidentiality. Integrity and confidentiality are now becoming more important since vehicles are becoming more and more networked with the external world, for example, car-to-car or car-to-road communications.