vrIpNhrpNhcIdleDetectTimePeriod 1.3.6.1.4.1.562.2.4.1.100.6.19.3.10.1.4

This attribute, along with idleDetectPacketCount, specifies the idle shortcut threshold; If the number of frames transmitted over an outgoing shortcut, or received over an incoming shortcut, within the time interval specified by idleDetectTimePeriod falls below the value specified by idleDetectPacketCount, then the shortcut connection will be released.