text: Area Defense
  CONTROL MEASURES FOR AN AREA DEFENSE
  9-14. Units organize their area defense by designating engagement areas. Using the seven steps of EA
  development, defending units determine where to place BPs and how best to assign areas to subordinate units.
  Units create security areas in front of their MBAs. Security areas should be deep enough to make enemy
  forces displace as much of their supporting forces as possible, such as cannon artillery, sensors, and air
  defense artillery gun systems, before attacking. Units also designate echelon support areas.
  9-15. Area defense maneuver graphic control measures may include‒
  * Engagement areas.
  * Boundaries.
  * FEBA.
  * Battle handover lines.
  * Strong points.
  * TRPs.
  * NAIs.
  * TAIs.
  * Decision points.
  * Passage points.
  * Various other fire control and countermobility control measures.
  9-16. Figure 9-1 depicts example area defense control measures. Appendix A defines these defensive control
  measures.
  Figure 9-1. Example area defense control measures
  9-17. Commanders give their subordinate commanders specific guidance on the initial positioning of forces.
  Commanders ensure the synchronization of subordinate units’ defensive plans, and that control measures,
  such as contact points and phase lines, enable subordinate commanders and prevent fratricide. If subordinate
  unit commanders prepare their defensive plans in isolation, assailable flanks between subordinate units could