Communication Manager supports network preemption. For network preemption to work, Communication Manager must be configured to use Session Manager as the bandwidth manager. To configure Session Manager as the bandwidth manager, see Avaya Aura® Communication Manager Feature Description and Implementation. The security administrator can assign bandwidth budgets for audio and video, to each network link on Session Manager. When server or network resources are running too low to allow additional calls, call preemption occurs. For more information, see Administering Avaya Aura® Session Manager.