text: Chapter 5
  5-6. Commanders may need to designate one or more of their units to conduct supporting efforts to create
  windows of opportunity for executing their main effort. They use the minimal combat power necessary to
  accomplish their missions, since overwhelming combat power cannot be employed everywhere. Units
  conducting supporting efforts usually have a wider assigned area than those conducting the main effort.
  Commanders can assign the tasks of follow and assume or follow and support to subordinate units.
  RESERVE
  5-7. The strength and composition of the reserve vary with the mission variables, the form of maneuver,
  and the risk accepted. In an attack, the combat power allocated to the reserve depends primarily on the level
  of uncertainty about enemy forces, especially the strength of any expected enemy counterattacks. For
  example, in a hasty attack a reserve can contain up to one third of a force’s combat power. Alternatively,
  units size their reserve to defeat their enemy’s projected available counterattack forces in deliberate attacks.
  They should not constitute their reserves by weakening their main effort. A reserve requires mobility equal
  to or greater than the most dangerous enemy ground threat, and it should be able to counter that threat. See
  paragraphs 1-94 through 1-100 more information on a reserve.
  COMMON CONTROL MEASURES ASSOCIATED WITH AN ATTACK
  5-8. A higher echelon commander assigns the area to units conducting offensive actions within which they
  operate. Within these assigned areas, units at a minimum designate these control measures:
  * A phase line as the LD, which may also be the line of contact (LC).
  * The time to initiate the operation.
  * The objective.
  If necessary, a commander can assign an area (zone or area of operations) or use axis of advance, direction
  of attack, routes, or additional phase lines to further control maneuver forces. Figure 5-1 depicts common
  control measures associated with an attack.
  Figure 5-1. Example of attack control measures
  5-9. Units can use any other control measures necessary to control an attack. Short of the LD, units may
  designate assembly areas and attack positions where they prepare for offensive actions or wait for established
  required conditions to initiate the attack. Beyond the LD, units may designate checkpoints, PLs, probable