Two top-ranking executives have joined RealNetworks.

Founding member of XM Satellite Radio Robert Acker has been named VP of the RealPlayer business and Aref Matin, formerly an executive at Juniper Networks and Siemens, joins RealNetworks as VP of carrier and system software.

Acker will direct Real's RealPlayer business, including development, distribution and marketing of the RealPlayer.

Matin will assume the new role of vice president of carrier and system software. He will be responsible for software product development, solution integration services and technical customer support of RealNetworks' systems software solutions for both wireline and wireless networks.

RealNetworks founder and CEO Rob Glaser said: "Robert's background is a great fit. He helped to create the satellite radio industry and helped XM become number one in that business. Aref's experience at providing innovative and executive leadership to technology teams will be invaluable in leading our efforts to build our systems business."