A global distribution system (GDS) is a network that provides information about travel-related services. It is mostly used by travel agencies.
In essence, it is a business-to-business system that connects travel agents and travel service providers. It allows travel agents to make bookings for hotels, flights and car rentals all in one place.
Global distribution systems provide real-time data about the availability of travel services and their prices. They also allow automated transactions between the parties.
The most well-known GDSs are Travelport, Amadeus and Sabre.