Motorola today announced another acquisition meant to bolster its video-on-demand (VOD) portfolio today, purchasing software vendor Vertasent for an undisclosed sum.

Vertasent sells resource management software that allows on-demand and other IP video content to share network resources with other applications. The product entered beta tests in May 2005. The company promotes an open-standards switched digital video architecture aimed at serving the needs of cable companies in particular.

In January of this year, Vertasent announced a partnership with video-on-demand server vendor Broadbus, which Motorola announced in July it would acquire.

The VOD sector has seen a wave of consolidation and investment activity lately. Cisco Systems acquired software vendor Arroyo Video Solutions last month. Harmonic acquired Entone Technologies’ VOD software business the next day. And in June, Cisco and AT&T both invested in VOD content startup Akimbo Systems.

Although about 63 million U.S. households partake in VOD services today, a third of all the TV-watching households worldwide will use it by the end of this decade, according to Informa Media and Telecoms. Of the $211 million in revenue generated by IPTV services last year, $11 million — or about 5% — came from VOD. Informa predicts VOD revenue will reach $132 million by 2011, in an overall IPTV services market of $2.2 billion.