Binding Cache Entries for Session Continuity in Proxy Mobile IP
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Solution Overview
Problem
Current Proxy Mobile IP (PMIP) networks face challenges in maintaining session continuity when a terminal switches between multiple access gateways, leading to connectivity issues and session termination due to changes in home addresses.
Innovation Solution
The method involves storing binding cache entries for multiple gateways and subnet prefixes, allowing for seamless transfer of data flows between gateways while maintaining session continuity by informing both gateways of each other's session information and using flow indicators to redirect packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a terminal uses multiple access gateways simultaneously, then access versatility and connectivity options are improved, but session continuity and connectivity stability deteriorate due to home address changes
Solution Approach 1:
The LMA performs preliminary actions by storing multiple subnet prefixes in the binding cache before the terminal actually switches gateways. When a terminal attaches to a PMIP network, the LMA allocates and stores multiple HNP values (home network prefixes) in advance, so that when gateway switching occurs, the necessary binding information is already prepared and can be immediately applied without session interruption.
Solution Approach 2:
The LMA acts as an intermediary between multiple gateways and the terminal. It maintains a unified binding cache that stores binding information for multiple gateways (MAG1, MAG2, etc.) and coordinates the subnet prefix allocation and binding update processes. This intermediary role allows the system to manage multiple gateway connections consistently, ensuring that when a terminal switches between gateways, the LMA can redirect packets appropriately without disrupting the terminal's home address identity.
2Reliability
If multiple binding cache entries are stored for different gateways, then session continuity is improved, but device complexity increases
Solution Approach 1:
The binding cache entry structure is designed with multi-functionality to handle multiple gateways. Each binding cache entry stores a terminal identifier, multiple subnet prefixes, and gateway identifiers, allowing a single data structure to manage bindings for multiple gateways simultaneously. This universal approach consolidates what would otherwise require multiple separate binding mechanisms into one unified structure, reducing overall system complexity while maintaining the ability to support multiple gateways.
3Adaptability or versatility
If home addresses are changed when terminal moves between gateways, then adaptability to different access technologies is improved, but connectivity stability deteriorates due to session termination
Solution Approach 1:
The system changes the parameter of subnet prefix allocation based on gateway changes. Instead of using a fixed home address, the LMA dynamically allocates different subnet prefixes (HNP values) corresponding to different gateways. When a terminal switches from one gateway to another, the LMA updates the binding cache with the new subnet prefix and gateway identifier, allowing the terminal to maintain its home address identity while adapting to the new gateway. This parameter change approach enables gateway mobility without disrupting connectivity.
Data Source
AI summary
Methods and nodes are provided for supporting session continuity for terminals capable of having simultaneous accesses while served by a plurality of gateways. Distinct binding cache entries (BCE) are stored for a terminal, each BCE being related to one of the gateways serving the terminal. The BCEs identify the terminal, provide an address allocated thereto for getting access at a gateway, and identify the gateway providing the access. When detection is made that two of more BCEs relate to the same terminal for distinct gateways, address information is sent to each other gateway.