Direct MME-PCRF Interface for Dynamic Gateway Selection
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Solution Overview
Problem
Current mobile gateway selection mechanisms in communication networks, such as those in LTE and GERAN/UTRAN systems, lack the ability to dynamically consider advanced factors beyond DNS resolution, making it difficult to enforce common policies like maximum bandwidth and usage quotas across multiple sessions, especially in scenarios involving machine-to-machine communications and fixed mobile convergence.
Innovation Solution
A direct interface between the MME/S4-SGSN and PCRF nodes allows for dynamic mobile gateway selection, enabling the consideration of advanced factors and ensuring that all sessions of a user or group use the same gateway, through a negotiation mechanism that determines the PDN GW IP address based on policies and user subscription information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DNS resolution is used for gateway selection, then the process is simple and fast, but it cannot consider advanced factors like policies and user subscription information for dynamic gateway selection
Solution Approach 1:
The patent introduces a direct interface between the MME/S4-SGSN and PCRF as an intermediary mechanism. This interface enables the MME to forward gateway selection requests to the PCRF, which then returns selected gateways based on policy and subscription information. This intermediary approach allows complex gateway selection based on multiple factors while maintaining a relatively simple overall architecture by leveraging existing network components.
Solution Approach 2:
The patent implements preliminary action by having the MME prepare gateway selection requests before actual session establishment. The MME queries the PCRF in advance to determine the appropriate gateway based on user subscription information and network policies, and this pre-determined gateway information is then used during session setup. This preliminary gateway determination enables adaptive gateway selection without complicating the real-time session establishment process.
2Reliability
If dynamic gateway selection based on policies is implemented, then common policies like maximum bandwidth and usage quotas can be enforced, but the gateway selection process becomes more complex
Solution Approach 1:
The PCRF serves as an intermediary that handles complex policy evaluation and gateway selection. Instead of requiring the MME to implement complex policy enforcement logic, the MME simply forwards selection requests to the PCRF, which applies policy rules and returns appropriate gateway recommendations. This intermediary approach enables reliable policy enforcement while keeping the MME's processing logic relatively simple.
Solution Approach 2:
The patent implements feedback mechanisms where the PCRF provides feedback information to the MME about selected gateways based on policy evaluation. The MME receives feedback containing gateway selection recommendations from the PCRF and uses this information to establish sessions. This feedback loop enables dynamic policy-based gateway selection while maintaining a clear separation of concerns between the MME and PCRF.
3Adaptability or versatility
If a direct interface between MME and PCRF is established, then dynamic gateway selection is enabled, but the network architecture becomes more complex
Solution Approach 1:
The patent applies universality by designing the direct MME-PCRF interface to serve multiple functions. This interface not only enables gateway selection but also supports policy evaluation, session management, and other network control functions. By making this interface multi-functional, the patent reduces the need for separate dedicated interfaces for each function, thereby limiting the increase in architectural complexity while maintaining high adaptability.
Solution Approach 2:
The patent merges the gateway selection function with the existing MME-PCRF communication framework. Instead of creating a completely separate gateway selection system, the patent integrates gateway selection into the existing session management and policy control workflows between the MME and PCRF. This merging approach enables dynamic gateway selection while minimizing additional architectural complexity by reusing existing communication protocols and data structures.
Data Source
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AI summary
There is provided mobile gateway selection performed by a PCRF node in communication with an MME node or an S4-SGSN. The mobile gateway selection is based on a direct MME/S4-SGSN-PCRF interface. A request message for a Packet Data Network Gateway Internet Protocol address to be used for establishing a session for a first user equipment is transmitted from the MME/S4-SGSN to a Policy and Charging Rules Function node through a direct MME /S4-SGSN-PCRF interface. The Policy and Charging Rules Function node determines a PDN GW IP address to be used for establishing the session based on policies for the first user equipment and transmits the PDN GW IP address through the direct MME/S4-SGSN-PCRF interface to the MME/S4-SGSN.