ATD(Agency Trading Desk) is a kind of Advertiser solutions that uses DSP(Demand-Side Platform) as a tool. Trading desks are media buyers and re-sellers within an ad agency that help advertisers execute programmatic media buys.
To be updated later...
You may want to know more about real-time bidding system composed of DSP, SSP, DMP, ATD and ITD. Please refer following associated information for more information: