Swarming (military)
The proposal was published in the Journal of the Royal United Service Institution and a couple of years later a shorter article suggested that if the Soviets themselves had used SMAs in swarms in Afghanistan their COIN operations against the Mujaheddin would have been far more successful. Contemporary Western armies in Afghanistan can readily accept that swarming at the tactical and operational levels is appropriate, but the physical structure of the country rules out the currently available fighting vehicles. However, networked and swarming SMAs, again 5,000 in number, all armed with laser designators for the second echelon of conventional ground attack aircraft, would constitute force multipliers with a substantial impact.

Improved decision-making as a force multiplier: Swarming ties in well with the theories of the military strategist John Boyd, the "high-low mix" in which a large number of less expensive aircraft, coupled with a small number of extremely capable "silver bullet" aircraft, had the effect of a much larger force. Boyd's concept of quick action is based on the repeated application of the Boyd loop, consisting of the steps

Observe: make use of the best sensors and other intelligence available
Orient: put the new observations into a context with the old
Decide: select the next action based on the combined observation and local knowledge
Act: carry out the selected action, ideally while the opponent is still observing your last action.
Boyd's concept is also known as the OODA Loop, and is applicable to all military operations, as well as to civilian competition from sports to business.
These are a realization of Boyd's theories. A swarming case is any historical example in which the scheme of manoeuvre involves the convergent attack of five (or more) semiautonomous (or autonomous) units on a targeted force in some particular place. "Convergent" implies an attack from most of the points on the compass."

Saturation of air defenses: Due to the vulnerability of sophisticated air defense systems such as S-300 and S-400 to mass attacks from low flying cruise missiles, it is thought that swarm tactics are well suited for Suppression of Enemy Air Defenses (SEAD) missions using swarms of networked miniature spoofing decoy drones accompanying large numbers of JASSM-ER cruise missiles launched from mass fire platforms such as Rapid Dragon.

Swarming avoids fratricide: Prevention of fratricide, as well as the ability to make ad hoc swarming attacks on targets of opportunity, is one of the major goals of combat data networking among units down to the level of individual tanks and soldiers. Blue Force Tracker is an early vehicle-level synchronization system, also operating in helicopters. These systems are still new and undergoing considerable improvement. One fratricide incident in Afghanistan came from the users not understanding that their target designation device reinitialized, after battery replacement, to the position of their designator, not of the target. If the bomber had a beacon that gave the crew the precise location of the friendly troops, that would have been another way of avoiding attacking one's own troops.

Modern militaries and lower-intensity conflict: Alternatively, the US and other major powers may go to a more cooperative model, as in the foreign internal defense mission of special forces. In that model, which needs extensive lead time, the major power uses nonmilitary and military means to increase the capability of the host nation to resist insurgency.
Foreign internal defense includes the economic stabilization of host countries. In Thomas Barnett's paradigm,
the world is divided into a "connected core" of nations enjoying a high level of communications among their organizations and individuals, and those nations that are disconnected internally and externally. In a reasonably peaceful situation, he describes a "system administrator" force, often multinational, which does what some call "nation-building", but, most importantly, connects the nation to the core and empowers the natives to communicate—that communication can be likened to swarm coordination.
Swarming is not a panacea for conflict at all levels. If there is a significant military force preventing the system administrator from working on developing connections, the other part of the paradigm comes into play: the leviathan, a first-world military force that takes down the opposition regular forces. Leviathan is not constituted to fight local insurgencies, but major forces. Leviathan may use extensive swarming at the tactical level, but its dispatch is a strategic decision that may be made unilaterally, or by an established core group such as NATO, ASEAN, or the United Nations.
It is the job of the system administrator force to deal with low-level conflict, and there must be both resources and a smooth transition plan from Leviathan to System Administrator responsibility, of which a classic successful example were the Operation Rankin plans that covered several ways in which Nazi power might end which is more a mission for police, which certainly can include a militarized force like the Constabulary in the post-WWII occupation of Germany.
Swarming would allow major powers to rapidly respond to guerilla forces, but, given the appropriate synchronization and communications, the less powerful forces can use swarming themselves. Modern communications allows military units to stay widely dispersed.  The front, rear and flanks are disappearing from military conflict.  Swarming allows the military to fight everywhere.

Swarming and Third World nations: Swarming is advantageous to less powerful countries and groups, because it allows them to balance their disadvantage in firepower and numbers. Despite being less technically advanced, Communist forces made good use of swarming in Asia during the Cold War. The Chinese were able to make up for their lack of firepower by attacking from all sides and then quickly advancing to the rear. The Vietcong were famous from attacking from all directions out of nowhere and then quickly disappearing. When they did come into close contact, they used a technique called "hugging the belt", which meant they were too close for the US to employ air and artillery support. If the attackers "hugged" at several points, "pulsing" their attacks, they both neutralized external fire support, but also made it difficult for the US commander to know where to commit reserves.

Swarming principles in terrorism: Cordesman observes that swarming is a viable terrorist tactic against targets of opportunity.
Al-Qaeda, for example, uses a different form of swarming than those of advanced militaries, in which the general objectives of operational cells are agreed in a manner coordinated, but not continuously controlled by the core organization. Once the decision has been made on the general targets, the operational cells cut positive control links from the core, although they may still receive financial and other support. A signature of al-Qaeda operations has been multiple, near-simultaneous attacks, such as the several hijacked airliners in the 9/11 attacks, the closely spaced bombings aimed at US embassies in Tanzania and Kenya, and attacks on buses and trains in London. The attacks on trains in Spain had an additional dimension: not all the swarms were associated with al-Qaeda.
While John Arquilla, a professor at the Naval Postgraduate School, cites the ability to plan separate and widely dispersed attacks, coordinated by mobile communications that might originate from a cave on the Afghan-Pakistan border, he does not emphasize the apparent al-Qaeda technique of releasing operational units to local control, once the policy is set. See Clandestine HUMINT operational techniques.
The apparent al-Qaeda methodology of letting operational cells decide on their final dates and means of attack exhibit an operational pattern, but not a periodicity that could easily be used for an indications checklist appropriate for a warning center. Such lists depend on seeing a local pattern to give a specific warning.
Semiautonomous swarming, in which the actors occasionally interfere with one another, is seen in attacks on computer networks by loose confederations of malicious hackers. On occasion, especially when the attack uses a botnet, some of the units may try to overpower and control one another, as well as the target. One of the observations of the Center on Terrorism and Irregular Warfare was that unfocused mass disruption was not a useful terrorist, and by extension general military, tactic. The 9/11 attacks had symbolism. A cyberattack on a stock market would have symbolism.  For the political purposes of the swarm, there has to be a symbol to which observers need to connect the purpose of the attack.

See also: C4ISTAR
Defeat in detail
Battle of annihilation
Three-Dimensional (3D) Tactics Analysis
Cabbage tactics

References: 

External links: Shannon, William D.; Tsypkin, Mikhail; Arguill, John. (June 2008). "Swarm Tactics and the Doctrinal Void: Lessons from the Chechen Wars". Naval Postgraduate School. Monterey, California (Thesis)