Seen-IP transit subscriber notification provides RADIUS Accounting Start notification of the IP addresses and location of active subscribers within a parent AA service. This allows a PCRF to dynamically manage RADIUS AA subscriber policy (create, modify, delete) without requiring static network topology mapping of a subscriber edge gateway to the parent transit service.
When detect-seen-IP is enabled within a transit policy, the ISA detects IP flows on an AA parent subscriber that do not map to an existing transit AA subscriber. It then uses a simple RADIUS Accounting Start notification from the transit AA node to the PCRF to initiate subscriber creation, providing information about the location of the transit subscriber traffic. This provides notice for subscriber authentication changes, such as new subscriber sessions or new host IP addresses added to an existing AA subscriber, while being independent of the network topology for how the BNG is homed into the transit AA nodes.
The RADIUS Accounting Start message is sent to the RADIUS Server referenced by the specified seen-ip-radius-acct-policy. This RADIUS message contains the following information about the flow:
subscriber-side IP address
parent SAP or spoke-SDP ID (NAS port ID)
IP address of node making the request
peer SAP or spoke-SDP ID (NAS port ID), if configured
peer IP address of SR making the request, if configured
AARP ID, if configured