text: Chapter 3
  JOINT SECURITY AREA
  3-121. A joint security area is a specific area to facilitate protection of joint bases and their connecting lines
  of communications that support joint operations (JP 3-10). The joint security area (JSA) is inside, or
  immediately adjacent to, an operational area where significant forces and sustainment from two or more
  services are positioned to conduct or support operations. Joint security on land includes bases,
  mission-essential assets, lines of communications, and convoy security. A senior Army commander is often
  designated with responsibility for joint security operations on land.
  3-122. The size of a JSA varies considerably and is highly dependent on the size of the operational area,
  mission-essential assets, logistics support requirements, threats, or scope of the joint operation. The JSA may
  be included in, be separate from, or be adjacent to the rear areas of the joint force land component commander.
  During large-scale combat operations JSAs typically are separate from land component or field army rear
  areas and associated support areas. (See JP 3-10 for more information on JSAs.)
  EXTENDED DEEP AREA
  3-123. The extended deep area is comprised of operational and strategic deep areas. These areas typically
  do not fall within the land component command’s AO, but they are part of its area of interest because enemy
  capabilities and vulnerabilities in the extended deep area can have significant impacts on the outcomes of
  operations. Extended deep areas are typically the purview of the joint force headquarters or another
  combatant command. Typically, the joint force air component command (known as the JFACC) is the
  supported command in extended deep areas. Army forces may be tasked to support it with long-range
  precision fires.
  3-124. Operational deep areas are generally inside the area of interest and immediately beyond the land
  component’s initially assigned AO. These areas may or may not be within the boundaries of a joint operations
  area (JOA) or a theater of operations. Operational deep areas are often beyond the feasible movement of
  conventional forces without significant support from the joint force.
  3-125. Operational deep areas contain enemy supporting formations and capabilities for their main forces.
  Enemy forces can generate significant combat power from these areas, and the capabilities that reside there
  are often vital to their conduct of operations. In most campaign designs, operational objectives for friendly
  forces reside initially in the operational deep area.
  3-126. Strategic deep areas are beyond the feasible range of movement for conventional ground forces or
  policy prohibits their operations. These areas are where the CCDR, other combatant commands, and national
  agencies can employ strategic intelligence capabilities, joint fires, special operations forces, and space and
  cyberspace capabilities. Many enemy space, cyberspace, and information warfare capabilities reside in
  strategic deep areas across international boundaries and outside the JOA, and they often comprise multiple
  areas of influence. (See figure 3-2 for a depiction of the operational framework.)