text: Chapter 5
  limited visibility. The early displacement of sustainment units can also prevent revealing friendly future
  operations to the enemy.
  5-231. Commanders anticipate the effects of retrograde movements on sustainment elements to ensure
  adequate support for the operation and the prompt evacuation of casualties. Retrograde movements generally
  result in increased distances between sustainment and combat units, which makes providing this support
  more difficult. Retrograde operations generally require more Class III and possibly more Class V supplies
  than during the other defensive operations. Increased supply of bulk fuel and ammunition combine to increase
  the demand for transportation assets and space on main supply routes. This, in turn, increases the need for
  movement control and pre-positioned services and supplies. Sustainment units carry and cache necessary fuel
  and ammunition stocks as required by the specific situation.
  DEFENSIVE OPERATIONAL FRAMEWORK CONSIDERATIONS
  5-232. In the defense, commanders typically retain the deep and rear areas, but they divide the close area into
  two distinct portions: the security area and main battle area. Commanders use this approach to synchronize
  operations, including those in air, space, and cyberspace, to defeat an enemy force throughout its depth. See
  FM 3-0 for additional information on defensive operational framework considerations.
  EXTENDED DEEP OPERATIONS
  5-233. Operational and strategic-level deep operations are typically outside an assigned land AO for a corps
  or division, but parts fall within the senior Army formation’s area of interest and area of influence. Army
  long-range fires, cyberspace, space, and other global capabilities support attacking targets in the extended
  deep area to set conditions for friendly defensive operations. Long-range artillery and ground-based missile
  capabilities can range enemy long-range missile batteries, manufacturing and economic nodes, critical
  infrastructure such as airfields and ports, strategic communications nodes, and strategic sustainment and
  reserve locations.
  DEEP OPERATIONS
  5-234. Deep operations are used to attrit, isolate, disrupt, and disorganize attacking formations and create
  windows of opportunity in which to act decisively against lead enemy echelons. The Army employs rocket
  artillery, rotary-wing aviation, unmanned aircraft systems, SOF, space and cyberspace capabilities,
  electromagnetic warfare, and influence activities to conduct deep operations.
  5-235. Sustainment capability employed to sustain deep operations is organic to Army organizations that
  execute long-range fires, rocket artillery, rotary-wing aviation, cyberspace, space and other multidomain
  effects that support attacking targets in the deep area. Specific organizations include the multi-domain task
  force BSB, CAB ASB, fires brigade BSB, and FSCs supporting the long-range fires battalion, rocket artillery,
  and rotary wing aviation.
  SECURITY AREA OPERATIONS
  5-236. During the defense, the security force occupies an assigned area far enough forward of the forward
  edge of the battle area to protect main battle area units from surprise. Security forces provide early warning
  to give main battle area units time to reposition forces against enemy maneuver and to mitigate the effects of
  enemy medium-range fires. The Army employs maneuver brigades task organized with fires, engineers, and
  aviation to increase the ability of guard or covering forces to slow and disorganize the enemy, degrade the
  enemy’s security forces, and gain additional time for the defending commander.
  5-237. Sustaining security area operations is a challenge due to long LOCs and tempo of operations.
  Sustainment capability employed to sustain security area operations is organic to Army maneuver brigades
  and organizations that provide fires, engineer, and aviation support in the security area. Specific organizations
  include the maneuver brigade BSBs and FSCs supporting the field artillery, aviation, and engineer battalions.
  MAIN BATTLE AREA OPERATIONS
  5-238. The main battle area is where the commander intends to deploy the bulk of the unit’s combat power
  and defeat an attacking enemy force. The commander positions forces in the main battle area to block enemy