IMS-AGW Relay Candidate Insertion for NAT Traversal

Solution Overview

Problem

Current NAT traversal mechanisms in IMS networks often result in increased delays due to the unnecessary use of multiple nodes and relay servers in the communication path, which is unacceptable for time-sensitive real-time multimedia traffic such as streaming and video conferencing.

Innovation Solution

The proposed solution minimizes the number of nodes in the media communication path by using IMS-AGW nodes instead of TURN servers for ICE-based NAT traversal, allowing the IMS network to add only an IMS-AGW node as a relay candidate when necessary, and removing it from the path if not required, thus optimizing the communication path for multimedia sessions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If TURN servers are deployed for ICE-based NAT traversal, then NAT traversal capability is improved, but the number of nodes in the communication path increases causing increased latency

Engineering Contradiction:

ImproveNAT traversal capabilityVSAvoidlatency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the relay server functionality from the traditional TURN server deployment and integrates it directly into the IMS network infrastructure. The IMS network nodes themselves perform the relay function when needed, eliminating the need for separate TURN server infrastructure and reducing the number of hops in the communication path.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

IMS network nodes are given multi-functionality, serving both as core network elements and as relay servers for NAT traversal when required. This eliminates the need for dedicated TURN servers and reduces communication path complexity by having network nodes perform multiple functions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple relay servers are deployed for NAT traversal, then NAT traversal reliability is improved, but device complexity and resource deployment increase

Engineering Contradiction:

ImproveNAT traversal reliabilityVSAvoidrelay server deployment

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes IMS network nodes universal by enabling them to function as relay servers in addition to their core network functions. This eliminates the need for separate TURN server infrastructure and reduces communication path complexity by having network nodes perform multiple functions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the relay server functionality with the IMS network infrastructure. Instead of having separate TURN servers, the relay function is combined with existing IMS network nodes, reducing overall system complexity and resource deployment requirements.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If TURN servers are used for NAT traversal, then NAT traversal capability is improved, but resource utilization efficiency decreases

Engineering Contradiction:

ImproveNAT traversal capabilityVSAvoidresource utilization efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent makes IMS network nodes universal by enabling them to function as relay servers in addition to their core network functions. This eliminates the need for separate TURN server infrastructure and reduces communication path complexity by having network nodes perform multiple functions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the relay server functionality with the IMS network infrastructure. Instead of having separate TURN servers, the relay function is combined with existing IMS network nodes, reducing overall system complexity and resource deployment requirements.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9137200B2Ice based NAT traversal

Publication Date: 2015.09.15 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

An originating P-CSCF node receives a SIP INVITE request from first user equipment (UE) that originates a call to a second UE. If a relay candidate address for the first UE is not present in the SIP INVITE request, the SIP INVITE request is modified to include a first address provided by an originating IMS-AGW node as a relay candidate for the first UE and forwarded to the second UE. The originating P-CSDF node receives a SIP INVITE response message from the second UE in response to the SIP INVITE request. If a relay candidate address for the second UE is not present in the SIP INVITE response, the SIP invite response is modified to include a second address provided by an originating IMS-AGW node as a relay candidate for the second UE and forwarded t the first UE. The address information is used by both UEs in ICE operations.