A GDS is an old, colossal computer network that transmits the availability and prices of airlines, car rentals and hotels to travel agencies. Connecting a hotel directly to a GDS is very difficult; this is why hotels usually connect via a GDS provider. A GDS provider will connect the hotel directly to all major GDS systems and will also take care of the sales and marketing activities. These providers integrate with Channel Managers and CRS’s, so maintaining this channel costs little effort.