Intermediate Node Macro-Mobility Routing via Address Mapping

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Solution Overview

Problem

Current network-layer protocols, such as IPv4, do not provide macro-mobility, leading to session termination when a node changes its network-layer session, and existing solutions like Mobile IP (MIP) suffer from increased complexity and packet overhead due to triangular routing, while Not Mobile IP (NMIP) requires modifications to IP stacks for compatibility.

Innovation Solution

A method and device for routing packets in a packet-switched network that enables macro-mobility by exchanging lower-layer address update messages and mapping source and destination addresses between a mobile node and a correspondent node, allowing communication as if both nodes are macro-mobility enabled, even if only one is, using an intermediate node that performs DHCP services and Network Address Port Translation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Mobile IP (MIP) protocols are used to provide macro-mobility, then nodes can change network-layer sessions without terminating conversations, but the system complexity and packet overhead increase due to triangular routing

Engineering Contradiction:

Improvemacro-mobility supportVSAvoidrouting complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the mobility management functionality from the core IP protocol stack and places it in an application-layer component. This allows macro-mobility to be implemented without modifying the underlying IPv4/IPv6 stacks, avoiding the complexity of triangular routing while maintaining conversation continuity through application-layer address updates

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of having the network layer manage mobility (as in MIP), the patent inverts the approach by implementing mobility management at the application layer. This reversal allows nodes to maintain conversations during network-layer session changes without requiring complex network-layer routing modifications

Inventive Principle:

Principle #13The other way round (Inversion)

2Device complexity

If Not Mobile IP (NMIP) is implemented to avoid triangular routing, then routing complexity is reduced, but compatibility issues arise with existing IP stacks that require modification

Engineering Contradiction:

Improverouting complexityVSAvoidIP stack compatibility

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements mobility management partially at the application layer rather than requiring full IP stack modification. This partial implementation allows NMIP functionality to be added to existing IPv4/IPv6 stacks without complete redesign, reducing compatibility issues while avoiding triangular routing

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The application-layer mobility manager is designed to work with existing IPv4 and IPv6 stacks without modification, providing universal compatibility. It handles address updates and conversation maintenance across different IP versions, allowing NMIP to function alongside traditional IP protocols

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If application-layer mobility management is implemented, then backward compatibility with existing IP stacks is maintained, but the ability to manage mobility in nodes that cannot be modified is limited

Engineering Contradiction:

ImproveIP stack compatibilityVSAvoidmacro-mobility management capability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an intermediary mobility manager at the application layer that mediates between nodes with and without native mobility support. This intermediary can act on behalf of non-modifiable nodes, receiving address updates and maintaining conversations even when the remote node cannot process mobility protocols directly

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9480090B2Method and system for optimising routing between two network nodes, at least one of which is mobile

Publication Date: 2016.10.25 ALCATEL LUCENT SA

AI summary

A method is disclosed for routing packets in an intermediate node between a mobile node and a correspondent node in a packet-switched network, only one of said nodes being macro-mobility enabled, comprising at the intermediate node: —exchanging lower-layer-address-update-related messages with said macro-mobility enabled node; —mapping source address, destination address and potentially protocol parameters of lower-layer packets exchanged between the mobile node and the correspondent node in such a way that the macro-mobility enabled node can communicate with the other node as if the other node is also macro-mobility enabled, and such that the other node can communicate with the intermediate node as if the intermediate node is a non-macro-mobility-enabled node. Also associated devices, update methods for devices, and servers are disclosed.