The value of this object defines how this X25 MLP logical port may use additional PSTN links to transmit temporary excess traffic (overflow mechanism). When opening or closing additional PSTN links the existing VCs are not cleared, so this overflow mechanism does not alter the communication between the two extremities. The possible values are : off : overflow is never enabled, onSlave : overflow is enabled by the connected equipment, onMasterWhileActivity : when the traffic overtakes the fclX25MlpOvOverflowThreshold value for all the links in use (line interfaces and eventual PSTN links), a new PSTN link is open by the equipment and remains active while at least one X25 VC is using this way. When no VC is active, this PSTN link is closed. onMasterWhileExcessTraffic : when the traffic overtakes the fclX25MlpOvOverflowThreshold value for all the links in use (line interfaces and eventual PSTN links), a new PSTN link is open by the equipment and remains active while the traffic is overtaking the fclX25SlpOvOverflowBackThreshold value. When the traffic does not overtake any more the fclX25SlpOvOverflowBackThreshold value, this PSTN link is closed. When one line interface is DOWN its bandwith is considered as being 0. So the overflow mechanism may be used as a backup mechanism which permits to not clear existing VCs. The default value is 'off'.