Diameter Routing Agent PCRF Selection for Roaming Networks
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Solution Overview
Problem
The challenge lies in selecting a Policy and Charging Rules Function (PCRF) for an IP-CAN session to associate the Policy and Charging Enforcement Function (PCEF), Bearer Binding and Event Reporting Function (BBERF), and Application Function (AF) with the same PCRF, especially when a User Equipment (UE) roams across different networks.
Innovation Solution
A method where a Routing Agent (DRA) in the visited network selects a PCRF for the UE by forwarding session establishment requests, either directly or through redirection messages, ensuring that PCEF, BBERF, and AF are associated with the correct PCRF within the home or visited network, depending on the roaming architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DRA selects a PCRF for an IP-CAN session during UE roaming, then the association between PCEF, BBERF, and AF with the same PCRF is ensured, but the complexity of selecting and routing session establishment requests through visited and home network DRA s increases
Solution Approach 1:
The patent introduces DRA (Diameter Routing Agent) as an intermediary entity that mediates between PCC clients (PCEF, BBERF, AF) and PCRF. The DRA receives session establishment requests from multiple sources, performs intelligent routing decisions, and forwards requests to the appropriate PCRF. This intermediary structure ensures that all PCC clients are associated with the same PCRF while simplifying the overall system architecture by centralizing the selection logic in the DRA rather than requiring direct complex interactions between all network elements.
2Reliability
If session establishment requests are routed through multiple DRA s (visited and home network), then the correct PCRF is selected according to roaming architecture, but the signaling overhead and message forwarding time increase
Solution Approach 1:
The patent implements preliminary action by having the visited network DRA perform PCRF selection and establish the association between PCC clients and PCRF during the initial session establishment request. The visited DRA selects an appropriate PCRF based on the roaming architecture (Home Routed or Local Break) and pre-establishes the routing path. Subsequent requests from BBERF and AF are then efficiently routed through the already-established path, avoiding repeated selection processes and reducing signaling overhead for later interactions.
Solution Approach 2:
The patent segments the PCRF selection and routing process into distinct phases: (1) initial PCRF selection by visited DRA upon receiving first session establishment request, (2) association recording in visited DRA, (3) efficient routing of subsequent requests through home DRA to the selected PCRF. This segmentation allows the complex selection logic to be executed once during initial setup, while subsequent operations benefit from the pre-established routing information, reducing overall signaling time and overhead.
Data Source
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AI summary
A method for selecting a policy and charging rules function. When a UE accesses a 3GPP system through a roaming architecture, upon receiving a session establishment request message sent by a PCC client located in the visited network, the DRA in the visited network forwards the message to a selected PCRF of the visited network according to the records stored locally or instructs the PCC client to transmit the session establishment request message to the selected PCRF of the visited network; and the PCRF of the visited network forwards the session establishment request message to a DRA of a home network, then the DRA of the home network forwards the message to the selected PCRF of the home network according to the records stored locally or instructs the PCRF of the visited network to transmit the session establishment request message to the selected PCRF of the home network.