In general, this disclosure is directed to establishment and release of a connection between a communication device and an access network. More specifically, the techniques of this disclosure are directed to determining when a data flow used for exchanging call control requests becomes inactive. For example, a communication device may dynamically adjust an inactivity timer threshold associated with the data flow used by applications to exchange call control messages when a new call control transaction starts or an existing call control transaction ends, e.g., by selecting a single inactivity timer threshold for the data flow to satisfy minimum connection requirements of existing call control transactions, recently ended call control transactions and the new call control transaction. The data flow is considered inactive when no applications send or receive messages via the data flow for a period of time that exceeds the adjusted inactivity timer threshold.