Global distribution system

A Global Distribution System (GDS) is a network operated by a company that enables automated transactions between travel service providers (mainly airlines, hotels and car rental companies) and travel agencies. Travel agencies traditionally relied on GDS for services, products & rates in order to provision travel-related services to the end consumers. A GDS can link services, rates and bookings consolidating products and services across all three travel sectors: i.e., airline reservations, hotel reservations, car rentals.

GDS is different from a computer reservations system, which is a reservation system used by the service providers (also known as vendors). Primary customers of GDS are travel agents (both online and office-based) to make reservation on various reservation systems run by the vendors. GDS holds no inventory; the inventory is held on the vendor's reservation system itself. A GDS system will have real-time link to the vendor's database. For example, when a travel agency requests a reservation on the service of a particular airline company, the GDS system routes the request to the appropriate airline's computer reservations system. This enables a travel agent with a connection to a single GDS to choose and book various flights, hotels, activities and associated services on all the vendors operating in the same route who are part of that GDS network.

A mirror image of the passenger name record in the airline reservations system is maintained in the GDS system. If a passenger books an itinerary containing air segments of multiple airlines through a travel agency, the passenger name record in the GDS system would hold information on his entire itinerary, each airline he flies on would only have a portion of the itinerary that is relevant to them. This would contain flight segments on their own services and inbound and onward connecting flights (known as info segments) of other airlines in the itinerary. e.g. if a passenger books a journey from Amsterdam to London on KLM, London to New York on British Airways, New York to Frankfurt on Lufthansa through a travel agent and if the travel agent is connected to Amadeus GDS. The PNR in the Amadeus GDS would contain the full itinerary, the PNR in KLM would show the Amsterdam to London segment along with British Airways flight as an onward info segment. Likewise the PNR in the Lufthansa system would show the New York to Frankfurt segment with the British Airways flight as an arrival information segment. The PNR in British Airways system would show all three segments. One as a live segment and the other two as arrival and onward info segments.

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