A global distribution system (GDS) is a computerised network system owned or operated by a company that enables transactions between travel industry service providers, mainly airlines, hotels, car rental companies, and travel agencies. The GDS mainly uses real-time inventory (for e.g. number of hotel rooms available, number of flight seats available, or number of cars available) to service providers. Travel agencies traditionally relied on GDS for services, products and rates in order to provide travel-related services to the end consumers. Thus, 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.