ALEXANDRIA, Virginia, May 2 (Reuters) - Alphabet's

Google will face a trial in September on antitrust

enforcers' proposals to make it sell off part of its advertising

technology business to address the company's dominance over

tools used by online publishers to sell ads.

U.S. District Judge Leonie Brinkema in Alexandria, Virginia,

set the trial date on Friday after hearing from Google and the

U.S. Department of Justice about potential remedies in the case.

Both sides are expected to file detailed proposals on

Monday.

The DOJ will seek to have Google sell off its ad exchange

and publisher ad server business, in a process expected to take

several years, said DOJ attorney Julia Tarver Wood.

Google lawyer Karen Dunn said the company supported

behavioral remedies - such as making real-time bids available to

competitors - but that prosecutors cannot legally pursue a bid

to force Google to sell parts of its business.

Such a move would also harm internet users and encounter a

lack of interested buyers, she said.

Publisher ad servers are platforms used by websites to store

and manage their digital ad inventory. Along with ad exchanges,

the technology lets news publishers and other online content

providers make money by selling ads.

Brinkema ruled in April that Google unlawfully tied

publishers' use of its ad exchange to use of its ad server, and

enacted anticompetitive policies that were "not in its publisher

customers' best interests." The conduct harmed competition, and

hurt publishers and ultimately internet users, she said.

Google has previously explored selling its ad exchange to

appease European antitrust regulators, Reuters reported in

September.