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Hub and spoke airline route structures. Los Angeles and Denver are used as hubs.

The spoke-hub distribution paradigm is a form of transport topology optimization in which traffic routes are organized as a series of 'spokes' that connect outlying points to a central 'hub.' Simple forms of this distribution/connection model may be contrasted with point-to-point transit systems in which each point has a direct route to every other point, and which was the principal method of transporting passengers and freight until the 1970s. The spoke-hub distribution model was pioneered by Delta Airlines in 1955, and revolutionized the transportation logistics industry after Federal Express demonstrated the value of the concept in the early 1970s. The distribution topology was subsequently adopted by the telecommunications and information technology sector in the late 1970s, and where it is known as the star network topology.

## Benefits

The hub-and-spoke model, as compared to the point-to-point model, requires less routes. For a network of n nodes, only n - 1 routes are necessary to connect all nodes so the upper bound is n - 1, and the complexity is O(n). That compares favourably to the ${\displaystyle {\frac {n(n-1)}{2}}}$ 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 10 destinations, the spoke-hub system requires only 9 routes to connect all destinations, and a true point-to-point system would require 45 routes. The small number of routes may also lead to more efficient use of transportation resources. For a same number of aircraft, having less 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.

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

## Drawbacks

Because the model is centralised, day-to-day operations may be relatively inflexible, and changes at the hub, even in a single route, may have unexpected consequences throughout the network. It may be difficult or even impossible to handle occasional periods of high demand between two spokes. As a result of this, route scheduling is complicated for the network operator, since scarce resources must be used carefully to avoid starving the hub and careful traffic analysis and precise timing are required to keep the hub operating efficiently.[citation needed]

As well, the hub constitutes a bottleneck or single point of failure in 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.

Finally, since at least two trips are required to reach destinations other than the hub, distance travelled may be much longer than a direct trip between departure and destination points. The time spent at the hub increases the duration of the journey. Moreover, the importance of the hub operating efficiently means that delays can have more troublesome consequences, such as missing a connecting bus, flight, or train.[citation needed]

## Commercial aviation

In 1955, Delta Air Lines pioneered the hub and spoke system at its hub in Atlanta, Georgia,[1] in an effort to compete with Eastern Air Lines. In the mid-1970s FedEx adopted the hub and spoke model for overnight package delivery. After the airline industry was deregulated in 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 use focus cities to 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:

For passenger road transport, the spoke-hub model does not apply because drivers generally take the shortest or fastest route between two points.

## Industrial distribution

The hub-and-spoke model has also been used in economic geography theory to classify a particular type of industrial district. Ann Markusen, an economic geographer, 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 include Seattle (where Boeing was founded), Silicon Valley (a high tech hub), and Toyota City, with Toyota.

## East Asian relations

In the sphere of East Asian relations, according to Victor Cha, hub-and-spokes refers to the network of bilateral alliances between United States and other individual East Asian countries. The system constructs a dominant 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 like South Korea, Taiwan, and Japan are its "spokes." There is a strong alliance between the hub and the spoke, but there are no firmly established connections between the spokes themselves.[2]

This system was famously inspired by John Foster Dulles, the US Secretary of State from 1953 to 1959. He used the term twice in Tokyo and once at the San Francisco Peace Treaty of September 1951, which led to talks for bilateral peace treaty between the US and Japan.

The 1951 Security Treaty Between the United States and Japan, the 1953 U.S.-South Korea Status of Forces Agreement and the 1954 Sino-American Mutual Defense Treaty (later replaced by the Taiwan Relations Act) are some examples of such bilateral relations.[3]

In April 2014, all ten ASEAN defense chiefs and United States Secretary of Defense Chuck Hagel attended the US-ASEAN Defense Forum in Hawaii. That was the first time the US hosted the forum. It was part of a US attempt to get the countries to strengthen military ties between themselves.[4]