NAT64 Home Agent Mobility Management for IPv6-IPv4 Translation

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Solution Overview

Problem

Existing NAT64 solutions face challenges in handling mobility management for mobile nodes (MNs) when transitioning between different wireless access networks, leading to prefix mismatches and inefficient keep-alive mechanisms that drain battery power and hinder proper packet translation and multicast support.

Innovation Solution

Implementing a system that includes a Home Agent (HA) and a NAT64 server, which uses a NAT state table to associate IPv6 addresses with IPv4 addresses, enables reverse tunneling for MNs, and employs an improved keep-alive mechanism to conserve battery power, while supporting multicast translations and disabling route optimization to ensure seamless communication between IPv6-only MNs and IPv4-only hosts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional NAT64 solutions are used for mobile nodes, then packet translation between IPv6 and IPv4 is enabled, but prefix mismatches occur when MNs transition between different wireless access networks

Engineering Contradiction:

Improvemobility managementVSAvoidpacket translation accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system dynamically updates the binding cache entry with the current care-of address when a mobile node transitions between access networks. The HA receives a Binding Acknowledgement message containing the new care-of address, updates the binding cache accordingly, and sends a Binding Update message to the MN. This dynamic update mechanism ensures the binding cache always reflects the current network location, resolving prefix mismatch issues during mobility.

Inventive Principle:

Principle #15Dynamics

2Reliability

If frequent keep-alive messages are sent to maintain NAT state, then connection stability is improved, but battery power is drained

Engineering Contradiction:

Improveconnection stabilityVSAvoidbattery power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of continuous or frequent keep-alive messages, the system uses a periodic action triggered by actual data traffic. When data packets are received or sent, the NAT state is automatically refreshed without requiring separate keep-alive messages. This event-driven periodic refresh maintains connection stability while eliminating unnecessary periodic signaling that would drain battery power.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system implements feedback mechanisms where the NAT state is automatically updated based on actual packet flow conditions. The binding cache entry is updated with new care-of addresses received from mobility management messages, and NAT state transitions are triggered by actual data packets rather than artificial keep-alive signaling. This feedback-driven approach maintains reliability without energy waste.

Inventive Principle:

Principle #23Feedback

3Productivity

If route optimization is enabled for mobile nodes, then communication efficiency is improved, but multicast support and packet translation reliability deteriorate

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidmulticast support

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system extracts and disables route optimization functionality for mobile nodes that need reliable multicast support and packet translation. By taking out the route optimization feature from the mobile node configuration, the patent ensures that packets are routed through the home agent and NAT64 server, maintaining reliable translation and multicast support while sacrificing some communication efficiency.

Inventive Principle:

Principle #2Taking out (Extraction)

4Measurement precision

If NAT state table entries are frequently updated to track mobile node location, then mobility management accuracy is improved, but processing overhead and system complexity increase

Engineering Contradiction:

Improvelocation tracking accuracyVSAvoidsystem processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by receiving and processing Binding Acknowledgement messages from mobile nodes before actual data transmission begins. The HA updates the binding cache entry with the care-of address in advance, establishing accurate location tracking before packet flow starts. This preliminary location registration simplifies subsequent packet routing and reduces real-time processing complexity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8665873B2Network address translator 64 for dual stack mobile internet protocol version six

Publication Date: 2014.03.04 FUTUREWEI TECHNOLOGIES INC

AI summary

An apparatus comprising a home agent (HA) configured to couple to a mobile node (MN), a network address translation (NAT) server, and an Internet Protocol (IP) version four (IPv4) only host and to associate an IP version six (IPv6) address for an interface with the MN with an IPv4 address for an interface with the IPv4 only host in a NAT state table entry, wherein the NAT state table entry is used to translate an IPv6 packet associated with the MN to an IPv4 packet associated with the IPv4 only host.