Spoke-hub distribution paradigm
The term hub -and-spoke, spokes and hub and spoke architecture is used in transportation and in Information Technology. Generally it is meant that the connection between two end nodes A and B not directly, but via a central node Z, the hub (English: stroke ), is performed. The compounds of the end nodes A, B to node Z is referred to here as spokes (English: spokes ). In a system with a plurality of hubs, the path from node A in the range Z1 of the stroke results in a node B in the range of the stroke of Z2 from A to B, Z1 and Z2, even when the direct link and A would be less technically feasible to B. The transport cost is to be minimized subject of Umladeproblems a optimization problem in the field of logistics.
- 2.1 Enterprise Application Integration
- 2.2 Network Technology
- 2.3 telephony
Hub and spoke transportation
In hub and spoke is understood in transportation a star-shaped arrangement of transport routes, which all run on one or by a central node in all directions in order to serve the area can (star topology).
A distinction hub-and -spoke systems with single assignment (Single Allocation ) and multiple assignment (multiple allocation). When using single assignment each source and each sink has exactly one connection to exactly one hub. With multiple sources and sinks assignment to multiple hubs can build connections. The single allocation is thus a special case of multiple association. In addition, there are hub and spoke systems without direct (pure hub & spoke systems) and systems with direct connections ( hybrid hub & spoke systems) between the Nichthubknoten.
Application found this system in the late 1970s in commercial air transportation within the United States. Reason for this was and is the bundling of traffic flows and the corresponding demand, so that it comes to optimizing utilization of transport vehicles used by empty or empty leg flights are avoided. Through the system, the law of economies of scale is used, thus saving costs in contrast to the use of point- to- point traffic ( direct ). A disadvantage of this system is that the transport compared to a direct transport from point A to point B extended. ( See also transport network structure )
Of importance, this system is in almost all means of transportation:
- Maritime transport, where it is used there indirectly feeder traffic
- Air freight traffic, such as at major courier express parcel services ( CEP ) services such as UPS or Deutsche Post. At Deutsche Post Frankfurt is used as a hub for air freight. At UPS, it is the Cologne / Bonn Airport.
- Rail passenger transport: mainly long-haul focus on the connections between the airport locations and associated decommissioning shorter direct distance calls ( example: Hagen- Frankfurt via Cologne instead of Siegen- casting ) and therefore decoupling also such major cities of rail transport, interurban in a direct journey remaining transport with shorter paths and additional holding the individual trains therefore additionally a necessary change trains and fare calculation only through the hub even when use of shorter direct route; Also aside from shorter, lying near hubs, but across these routes;
- Rail freight both in single wagonload traffic with focus on very few marshalling yards as hubs as well as in container traffic in combined transport.
- Road transport, with all groupage forwarding company to offer in Germany a 24 -h and Europe a 48 -hour transport ( groupage ) to be able to.
- Another area of application package service dar. Here are the collected in the depots in addition to running packages consolidated in the so-called main run and handled through a hub. The spokes (the spokes ) Thus, the compounds of the stroke to the depots dar. But usually you can find a hybrid of the two network alternatives, deposits with a high mutual relationship through a large parcel volume between the two are mostly by point- to-point connections, also called direct services, interconnected; through the hub run mainly those packets whose sender or recipient depots identify any full truckloads.
Even systems with multiple hubs that are connected again by means of direct services that are possible. An example of this is the network of GLS Germany; The company refers to the hubs as ' central transhipment points ' ( LEP ).
In the private motorized hub-and -spoke method is virtually meaningless, since the driver usually the shortest path (possibly with minor detours on highways instead of roads ) drives. In contrast, however, when acquired Mitfahren ( " hitchhiking " ), where depending on the method and traffic cities, motorway stations and border transitions get Hub Properties.
Hub and Spoke in the commercial passenger aviation
Almost all the major commercial airlines put at its hubs a the hub-and -spoke method for all their flights. Exception are the arisen in the 1980s and booming since the 90s so-called low cost airlines that offer mostly point-to -point connections. Through the hub-and -spoke method, it is in contrast to point- to-point method possible, a far greater number of connections, but with correspondingly more frequent Umsteigenotwendigkeit to offer.
Arithmetical
A system of transport endpoints with the connecting paths can be abstracted as an undirected graph without multiple edges. For the number of connections needed to per pairs to connect all the nodes together gives:
In hub-and- spoke traffic:
Compounds, the complexity is O (n)
When used exclusively P -P transport:
Compounds, the complexity is O ( n2)
In hub-and- spoke traffic to hubs:
Maximum connections
Example with airports
In a system of airports is the number of different individual compounds necessary to all airports from a selected central hub to interconnect 9, while for PP transports various flight connections would be necessary.
Hub and Spoke in Information Technology
Enterprise Application Integration
As a hub-and- spoke architecture or hub - and -spoke architecture in Information Technology refers to a form of integration of business functions on the basis of an exchange of messages or service requests is conducted in all traffic through a central integration platform. She is one of the possible topologies for Enterprise Application Integration. This is called also by the Business Bus, the terms are not completely synonymous.
Network Technology
In the network technology, the star topology plays a crucial role in networking with the help of twisted pair cabling. The individual network nodes are respectively connected to central hubs or switches which in turn are connected to each other. The term hub is used in network technology primarily used for a particular device type for the central network node. However, this type of device plays only a minor role in larger networks, or the rebuilding of networks and is largely replaced by switches. The network topology change does not affect, viewed topologically so that switches are also hubs.
Telephony
Telephone networks are also constructed largely in the form of a hub-and -spoke topology. The switches and telephone systems, the hubs and terminals form the spokes. In the field of digital telephony based on ISDN, there are also bus architectures.