text: Appendix E
  E-23. These obstacles, direct-fire positions, and active deterrents can be in the form of—
  * Wire, concrete, or other barriers used to reinforce the perimeter.
  * Entry control points and associated obstacle/countermobility plans used to canalize and control
  incoming personnel or vehicles.
  * Barriers employed to block high-speed avenues of approach, externally on approaches to the
  perimeter and internally to protect high-risk targets.
  * Perimeter guard towers and observation posts.
  * Ditches, berms, or other earthen obstacles.
  * Mobile security patrols.
  * Communications signal/electromagnetic signature masking.
  BASE CAMP AND BASE CLUSTER SECURITY
  E-24. Base camps provide a protected location to project and sustain combat power. While some base camps,
  especially smaller base camps built in high-threat areas, may be required to focus on defense rather than just
  security, the primary focus for most base camps is not on conducting defense, except in rare instances. In
  these cases, normal mission operations on the base camp cease and the focus of all available assets is shifted
  to defense until the threat is eliminated or repelled. Once the threat is defeated, the base camp and its tenant
  or transient units return their focus to their primary missions.
  E-25. Security operations are those operations performed by commanders to provide early and accurate
  warning of enemy operations, to provide the forces being protected with time and maneuver space within
  which to react to the enemy, and to develop the situation to allow commanders to effectively use their
  protected forces (ADP 3-90). The five fundamentals of security are—
  * Provide early and accurate warnings. Early and accurate warnings of an enemy approach are
  essential to successful base camp and base cluster protection/force protection. The base camp and
  base cluster commanders need information to shift and concentrate forces to meet and defeat the
  enemy. The use of OPs, patrols, security forces, and sensors provide long-range observation;
  observe enemy movement; and report the enemy’s size, location, and activity.
  * Provide reaction time and maneuver space. Base camp and base cluster security assets—forces,
  sensors, and patrols—should work at a sufficient distance to allow the base camp and base cluster
  commanders time to review rapidly reported information. This timely review gives the base camp
  and base cluster commanders the reaction time necessary to order indirect fire to slow the enemy’s
  rate of advance; maneuver direct-fire elements into place to engage, exploit, and defeat the enemy;
  and initiate coordination for a response force or TCF if required, based on the threat level.
  * Orient on the force, area, or facility to be protected. Base camp and base cluster organic,
  security, and reinforcement forces must be aware of any enemy movement and must reposition
  their elements accordingly to maintain their position relative to any threats. The force must
  understand the base camp and base cluster commander’s scheme of protection, including where
  the security force is in relation to enemy movement.
  * Perform continuous area security operations. Base camp and base cluster personnel conduct
  continuous area security operations to gain as much information as possible about the AO and any
  threats. This can be accomplished through OPs, mounted and dismounted patrols, and remote
  sensors, such as unmanned aircraft systems deployed to observe dead space.
  * Maintain threat contact. Once enemy forces are detected, base camp forces must continuously
  collect information on the enemy’s activities and disposition to assist the base camp or base cluster
  commander in determining the potential and actual enemy COA and deny the enemy the element
  of surprise. This requires security forces to maintain continuous visual contact to be able to use
  direct and indirect fires to influence enemy actions and gain time for the base camp and base
  cluster commander. Once the base camp security forces make enemy contact, they do not break
  contact unless the base camp or base cluster commander or a designated security force commander
  specifically directs it.