The dynamic address pool technology provides a mechanism to dynamically adjust address pool capacity. After having a dynamic address pool configured, a BRAS sends address segment requests or release requests to the RADIUS server based on its dynamic address pool's address usage and assigns obtained addresses to DHCP or PPP users.
A BRAS interacts with the RADIUS server through RADIUS to apply for or release address segments. A BRAS checks its dynamic address pool's address usage every 10 minutes. If the address usage exceeds the specified upper threshold, the BRAS initiates an address segment request; if the address usage falls below the specified lower threshold, the BRAS initiates an address segment release request.
A BRAS periodically detects the availability of obtained address segments. If the RADIUS server sends a detection success packet in response to the detection request sent by a BRAS, the BRAS can continue using the address segment specified in the detection request. If the RADIUS server sends a detection deny packet in response to the detection request, the BRAS cannot continue using the address segment.
If the address segment assignment packet sent from the RADIUS server to a BRAS gets lost during transmission, the assigned address segment will not be used by any device. To prevent this problem, the RADIUS server needs to periodically detect whether assigned address segments are in use. If some assigned address segments are not in use, the RADIUS server can release these address segments to improve address usage efficiency.