Terminal registration method, device, and system

An access point device, comprising:

• a first starting unit, configured to start a monitoring unit for the access point device when the access point device receives an access request message sent by a terminal;
• a first monitoring unit, configured to monitor a monitored resource, wherein there is a monitoring threshold recorded, and the monitoring threshold is a preset threshold for the monitored resource;
• and
• a stopping unit, configured to:
• after the terminal sends a registration request message to a database, if the access point device receives, when the monitored resource monitored by the first monitoring unit does not reach the monitoring threshold, a registration response message sent by the database, stop the monitoring on the monitored resource.

An access point device, comprising:

• a second starting unit, configured to start a monitoring unit for the access point device when the access point device receives an access request message sent by a terminal;
• a second monitoring unit, configured to monitor a monitored resource, wherein there is a monitoring threshold recorded, and the monitoring threshold is a preset threshold for the monitored resource;
• and
• a second detaching unit, configured to:
• after the terminal sends a registration request message to a database, if the access point device does not receive, when the monitored resource monitored by the second monitoring unit reaches or exceeds the monitoring threshold, a registration response message sent by the database, initiate a detaching process.