A network device is described in which a dedicated resource scheduler monitors memory consumption to provide for improved processing of communication sessions. The scheduler maintains a dependency list of communication sessions, and reserves memory for communication sessions as requests for memory are received. The amount of memory reserved is determined based on the amount of memory currently reserved for the communication sessions in the dependency list. The network device may control ongoing communication sessions by way of window manipulation. Communication sessions are processed in a first mode when available memory has not reached a predetermined amount, while communication sessions are processed in a second mode when available memory reaches a predetermined amount.