Releasing IPv4 Addresses During Termination of PPP Sessions

When a request for termination of the IPCP negotiation is received from the CPE, the B-RAS application running on the router acknowledges this terminate-request for closing the IPv4 session by sending a terminate-acknowledgment packet. If the IPCP termination is successful, the IPv4 address that the RADIUS server allocated to the client is released. The RADIUS client, which is the router, sends an immediate accounting message that contains the Ipv4-release-control RADIUS VSA attribute [26-164] to the RADIUS server. In this immediate accounting message, the Framed-Ip-Address RADIUS IETF attribute [8] is not included. This Acct-Update message is sent immediately on release of the IPv4 address to the RADIUS server and the configured interval for Interim-Acct messages is not considered in such a case. The Ascend-Data-Filter attribute [242] is modified to delete the Framed-IP-Address attribute for the released IPv4 address.

After the immediate accounting message is sent, the Interim-Acct message is sent to the RADIUS server at the configured interval. The Interim-Acct message contains all the supported RADIUS attributes except the Framed-Ip-Address attribute. Because the IPv6 addresses are not released in this scenario, the Interim-Acct message contains the IPv6 prefixes.