Departmentalization, Division of Labour, Span of Control and the 4th aspect of organizing effort is SCALAR RELATIONSHIPS – The Chain of Command.

Every organization is built on the premise that the individual at the top possesses the most authority and that other individual’s authority is scaled downward according to their relative position on the organization chart.
The lower a person’s position on the organization chart, then, the less authority that person possesses.
The Scale Relationship or Chain of Command is related to the unity of command.
UNITY OF COMMAND is the management principle that recommends that an individual  have only 1 boss.
If too many bosses give orders, the result will probably be confusion, contradiction and frustration –  a sure recipe for ineffectiveness and inefficiency in an organization.
Although the unity of command principle is 75 years old, it is still considered as a valid and critical one.
Fayol recommends that a gangplank be created for a peer level communication within and across departments with structures to keep the organization updated on the information shared.