Spoke–hub distribution paradigm

Thespoke–hub distribution paradigm(also known as thehub-and-spoke system) is a form oftransport topology optimizationin whichtraffic plannersorganize routes as a series of "spokes"that connect outlying points to a central" hub ". Simple forms of this distribution/connection model contrast withpoint-to-point transitsystems, in which each point has a direct route to every other point, and which modeled the principal method of transporting passengers and freight until the 1970s.Delta Air Linespioneered the spoke–hub distribution model in 1955,^[1]and the concept revolutionized thetransportation logisticsindustry afterFederal Expressdemonstrated its value in the early 1970s.^{[citation needed]}In the late 1970s thetelecommunicationsandinformation technologysector subsequently adopted this distribution topology, dubbing it thestar networknetwork topology.

"Hubbing" involves "the arrangement of a transportation network as a hub-and-spoke model".^[2]

Benefits

The hub-and-spoke model, as compared to thepoint-to-pointmodel, requires fewer routes. For a network ofnnodes, onlyn− 1routes are necessary to connect all nodes so the upper bound isn− 1,and thecomplexityis O(n). That compares favourably to the ${\frac {n(n-1)}{2}}$ routes, or O(n²), which would be required to connect each node to every other node in a point-to-point network. For example, in a system with 6 destinations, the spoke–hub system requires only 5 routes to connect all destinations, and a true point-to-point system would require 15 routes. However distance traveled per route will necessarily be more than with a point-to-point system (except where the route happens to have no interchange). Therefore, efficiency may be reduced. Conversely, for the same number of aircraft, having fewer routes to fly means each route can be flown more frequently and with higher capacity because the demand for passengers can be resourced from more than just one city (assuming the passengers are willing to change, which will of itself incur its own costs).

Complicated operations, such as package sorting and accounting, can be carried out at the hub rather than at every node, and this leads toeconomies of scale.As a result of this, spokes are simpler to operate, and so new routes can easily be created.

Drawbacks

In addition, the hub constitutes a bottleneck orsingle point of failurein the network. The total cargo capacity of the network is limited by the hub's capacity. Delays at the hub (such as from bad weather conditions) can result in delays throughout the network. Cargo must pass through the hub before reaching its destination and so require longer journeys than direct point-to-point trips. That may be desirable for freight, which can benefit from sorting and consolidating operations at the hub, but it is problematic for time-critical cargo, as well as for passengers. The necessity of baggage transfers at the hub also increases the risk of missing luggage, as compared to the point-to-point model.

Commercial aviation

In 1955, Delta Air Lines pioneered the hub-and-spoke system at its hub inAtlanta,Georgia,^[3]in an effort to compete withEastern Air Lines.In the mid-1970sFedExadopted the hub-and-spoke model for overnight package delivery. After the airline industry wasderegulatedin 1978, several other airlines adopted Delta's hub-and-spoke paradigm.

Airlines have extended the hub-and-spoke model in various ways. One method is to create additional hubs on a regional basis and to create major routes between them. That reduces the need to travel long distances between nodes near one another. Another method is to usefocus citiesto implement point-to-point service for high-traffic routes and to bypass the hub entirely.

Transportation

The spoke–hub model is applicable to other forms of transportation as well:

Sea transportin whichfeeder shipstransport shipping containers from different ports to a central container terminal to be loaded onto larger vessels.
Cargo airlines:mostUPS Airlinesflights travel through itsWorldportatLouisville International Airport,and manyFedEx Expressparcels are processed at its "SuperHub" atMemphis International Airport.
Freight rail transportin which cargo is hauled to a central exchange terminal. At the terminal, shipping containers are loaded from one freight car to another, andclassification yards(marshalling yards) are used to sort freight cars into trains and divide them according to varying destinations.Intermodal freightis often loaded from one mode to another at central hubs.
Public transituses varioustransport hubsto allow passengers to transfer between different lines or transportation modes. Often those hubs areintermodallinking buses, trams, local trains, subways and so on.

For passengerroad transport,the spoke–hub model does not apply because drivers generally take the shortest or fastest route between two points. However, the road network as a whole likewise contains higher order roads likelimited access highwaysand more local roads with most trips starting and ending at the latter but spending most of the distance on the former.

Industrial distribution

The hub-and-spoke model has also been used in economic geography theory to classify a particular type of industrial district. Economic geographer Ann Markusen theorized about industrial districts, with a number of key industrial firms and facilities acting as a hub, with associated businesses and suppliers benefiting from their presence and arranged around them like the spokes of a wheel. The chief characteristic of such hub-and-spoke industrial districts is the importance of one or more large companies, usually in one industrial sector, surrounded by smaller, associated businesses. Examples of cities with such districts includeSeattle(whereBoeingwas founded),Silicon Valley(a high tech hub), andToyota City,withToyota.

East Asian relations

In the context of East Asian geopolitics,Victor Chasays the hub-and-spokes paradigm refers to the network of alliances the United States has built individually with other East Asian countries. The 1951Security Treaty Between the United States and Japan,the 1953U.S.–South Korea Status of Forces Agreementand the 1954Mutual Defense Treaty between the United States and the Republic of China(later replaced by theTaiwan Relations Act) are some examples of such bilateral security relationships.^[4]The system creates a bilateral security architecture in East Asia that is different from the multilateral security architecture in Europe. The US acts as a "hub", and Asian countries likeSouth KoreaandJapanare its "spokes". There is a strong connection between the hub and the spoke, but weak or no connections between the spokes themselves.^[5]

In April 2014, all tenASEANdefense chiefs andUnited States Secretary of Defense Chuck Hagelattended the US–ASEAN Defense Forum in Hawaii. The meeting was the first time the US hosted the forum and was part of a US attempt to get the countries to strengthen military ties between themselves.^[6]

References

^"Delta's Firsts in the Airline Industry".
^"Hubbing".30 May 2018.
^Delta Air Lines Newsroom - Press Kit.Delta.com. Retrieved on 2013-08-16.
^Hemmer, C.;Katzenstein, P. J.(2002)."Why is There No NATO in Asia? Collective Identity, Regionalism, and the Origins of Multilateralism".International Organization.56(3): 575–607.doi:10.1162/002081802760199890.JSTOR 3078589.
^Cha, V. D.(2010). "Powerplay: Origins of the U.S. Alliance System in Asia".International Security.34(3): 158–196.doi:10.1162/isec.2010.34.3.158.S2CID 57566528.
^Keck, Zachary (2 April 2014)."US Swears Asia Pivot Isn't Dead".The Diplomat.Retrieved3 April2014.