Chain Of Command
The Chain of Command is the succession of commanders superior to subordinates through which command is exercised. The chain of command supports the NCO channel by legally punishing those who challenge a sergeant's authority. In a military context, the chain of command is the line of authority and responsibility along which orders are passed within a military unit and between different units. Orders are transmitted down the chain of command, from a higher-ranked soldier, such as a commissioned officer, to lower-ranked personnel who either carry out the order personally or transmit it down the chain as appropriate, until it is received by those expected to carry it out.
In general, military personnel give orders only to those directly below them in the chain of command and receive orders only from those directly above them. A service member who has difficulty carrying out a duty or order and appeals for relief directly to an officer above his immediate commander in the chain of command is likely to be disciplined for not observing the chain of command.
The concept of chain of command also implies that higher rank alone does not entitle a higher-ranking service member to give commands to anyone of lower rank. For example, an officer of unit "A" does not directly command lower-ranking members of unit "B", and is generally expected to approach an officer of unit "B" if he requires action by members of that unit. The chain of command means that individual members take orders from only one superior and only give orders to a defined group of people immediately below them.
There is no set size (number of troops) assigned to any specific element. The size of an element of command depends primarily upon the type of unit and mission. For example, an aviation company would have a different number of troops assigned than an infantry company because it has a different mission, different equipment, and therefore different requirements.