Originally Posted by
Indelaware
GDS's are global - hence the G. Most GDS are connected to most airlines.
The GDSes can talk to each other but each airline uses one as its primary CRS/PSS/sales system. United uses SHARES, for example, but Amadeus and Travelport and Sabre can also see the reservations.
There are also some smaller solutions like Navitaire and even an ITA-based offering which are typically used by smaller carriers or LCCs which don't need the interline options.
https://en.wikipedia.org/wiki/Comput...vations_system