Monitoring/supporting VOIP

I currently work for a borough Council and we support local schools. A few schools have now implemented a 3rd party VOIP system running over our network. Discussions are taking place now as to how we support/monitor this traffic.

We have various vendors of network equipment (Cisco, HP, Extreme) all monitored by Solarwinds.

My question is what would you guys advise us regarding support for VOIP across our network?