PCRF Selection Node Routing via DRA Intermediary
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Solution Overview
Problem
In communications networks with multiple PCRFs and DRAs, there is a need for efficient methods to select and assign PCRF nodes for users, ensuring that subsequent session-related traffic is routed to the same node, especially when scaling policy control functionality.
Innovation Solution
Implementing PCRF selection nodes that use subscriber identifiers like IMSI for static selection and dynamic criteria such as load balancing to determine the appropriate PCRF, allowing delegation of selection and maintaining local state to optimize routing and reduce the burden on other network components like PGWs and P-CSCFs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple PCRFs are added to scale policy control functionality, then network capacity and subscriber service capability are improved, but device complexity and routing management difficulty increase
Solution Approach 1:
The patent introduces a DRA (Diameter Routing Agent) as an intermediary component that sits between PGW/HSGW and PCRF nodes. The DRA receives session establishment requests from access network nodes, performs PCRF node selection based on subscriber identifiers, and routes requests to the appropriate PCRF. This intermediary approach centralizes the routing decision logic, eliminating the need for access network nodes to maintain complex routing tables with multiple PCRFs, thus scaling network capacity while managing complexity centrally.
Solution Approach 2:
The patent segments the PCRF selection function from the access network nodes (PGW/HSGW) and places it in dedicated DRA nodes. Each DRA is responsible for selecting PCRF nodes for specific subscriber groups based on subscriber identifiers. This segmentation allows independent scaling of PCRF nodes without requiring changes to access network nodes, enabling linear scalability while keeping access network simple.
2Ease of operation
If direct communication between PGWs/HSGWs and PCRFs is used, then communication simplicity is maintained, but update frequency and network overhead increase
Solution Approach 1:
The DRA acts as a persistent intermediary that maintains state information about subscriber-to-PCRF mappings. Once a PCRF is selected for a subscriber group, the DRA stores this information locally and uses it for subsequent routing decisions. This eliminates the need for PGW/HSGW to repeatedly query PCRF availability or receive updates about PCRF changes, as the DRA caches this information. Communication simplicity is preserved at the access network level while update frequency is reduced through intelligent caching and state maintenance at the DRA.
3Stability of the object's composition
If static PCRF selection based on subscriber identifiers is implemented, then routing consistency is improved, but adaptability to load balancing and node availability decreases
Solution Approach 1:
The patent implements a dynamic PCRF selection mechanism where the DRA can switch from static identifier-based routing to dynamic load-balancing-based routing. The DRA maintains local state information about subscriber-PCRF mappings but can update these mappings based on real-time conditions such as PCRF node availability, load levels, and network topology changes. This dynamic approach allows the system to adapt to changing network conditions while maintaining routing consistency for each individual subscriber session, balancing stability with adaptability.
Data Source
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AI summary
The subject matter described herein includes methods, systems, and computer readable media for PCRF node selection. According to one aspect, a system for PCRF node selection is provided. The system includes a first PCRF selection node for receiving a first request message for which PCRF node selection is required. The first PCRF selection node determines whether to select the PCRF or to delegate selection of the PCRF. In response to a determination to delegate the selection of the PCRF, the first PCRF selection node generates and sends a second request message related to the first request message. The system further includes a second PCRF node for, in response to receiving the second request message from the first PCRF selection node, determining whether to select the PCRF or to delegate selection of the PCRF. In response to determining to select the PCRF, the second PCRF selection node selects the PCRF.