3GPP Multi-Access Binding Cache for Seamless Handoff
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Solution Overview
Problem
Current 3GPP specifications do not adequately support simultaneous connectivity of a mobile node over multiple heterogeneous access networks, leading to issues in routing packets and performing handoffs between different access networks, particularly when a UE connects to a 3GPP access after a non-3GPP access, resulting in incorrect charging, flow deletion, and other unwanted behaviors.
Innovation Solution
A mechanism is introduced to enable the network to route packets correctly over multiple access networks by using a new flag or option in the Binding Update message to create a Binding Cache entry for flow binding, allowing the UE to perform handoffs between access networks, and utilizing IKE informational exchanges for flow binding information, ensuring seamless connectivity and flow management across different access types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE connects to a 3GPP access after a non-3GPP access using existing DSMIPv6 mechanisms, then the UE can establish connectivity over the new access, but incorrect charging and flow deletion occur due to lack of proper flow binding information
Solution Approach 1:
The patent applies preliminary action by establishing flow binding information in advance through IKE informational exchanges before the UE connects to 3GPP access. The home agent stores flow binding information including flow descriptors and care-of addresses associated with specific access networks, so that when handoff occurs, the charging and routing information is already prepared and preserved, preventing both incorrect charging and flow deletion.
2Adaptability or versatility
If multiple CoAs are registered for the same HoA with different binding descriptors, then routing can be performed based on flow binding, but the mechanism does not fully apply to 3GPP networks where home link detection prevents CoA assignment
Solution Approach 1:
The patent uses IKE informational exchanges as an intermediary mechanism to bridge the gap between DSMIPv6 flow binding requirements and 3GPP home link architecture. Instead of relying on CoA registration which is blocked by home link detection, the IKE exchange carries flow binding information to the home agent, enabling multi-access connectivity while maintaining compatibility with 3GPP protocols.
Solution Approach 2:
The patent changes the parameter representation by using flow descriptors and access network identifiers in IKE informational exchanges instead of traditional CoA-based binding descriptors. This allows the home agent to distinguish between different access networks and maintain appropriate routing and charging information without requiring CoA assignment on home links.
3Speed
If flow binding information is not preserved during access network transitions, then handoff can occur quickly, but routing packets to the correct access and performing seamless handoffs becomes impossible
Solution Approach 1:
The patent applies preliminary action by pre-establishing flow binding information through IKE informational exchanges before handoff occurs. The home agent stores flow descriptors, care-of addresses, and access network identifiers in advance, so that when the UE transitions between access networks, the routing information is already prepared and can be applied immediately, enabling both fast handoff and correct packet routing.
Data Source
AI summary
A method and apparatus for routing packets from a home agent to a user equipment through a first access network and a second access network. The method includes sending a first binding update message from the user equipment over the first access network to create a first binding cache entry at the home agent. The user equipment uses a home address assigned to the user equipment as a source IP address of the first binding update message. The method further includes sending a second binding update message from the user equipment over the second access network to create a second binding cache entry at the home agent. The user equipment receives packets from the home agent through the first access network and the second access network based on the first binding cache entry and the second binding cache entry.