Local TEL URI Resolution via DNS ENUM Query Construction

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Solution Overview

Problem

Existing methods for resolving local TEL Uniform Resource Identifiers (URIs) to addresses for routing across an IP network lack scalability and efficiency, particularly in handling non-globally unique phone numbers, as they require complex look-up tables and are difficult to update.

Innovation Solution

The solution involves constructing a domain name system query string by removing non-digit characters from a local TEL URI, reversing the digits, placing dots between them, and appending a Context Identifier, which is then used for a DNS lookup to retrieve a service URI, allowing for efficient routing through NAPTR records.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional look-up table methods are used to resolve local TEL URIs, then routing functionality is provided, but scalability and ease of updating are poor

Engineering Contradiction:
ImprovescalabilityVSAvoidcomplexity of look-up tables
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces a DNS server as an intermediary between the S-CSCF and the TEL URI resolution process. The S-CSCF generates a DNS query string based on the local TEL URI and sends it to the DNS server, which returns the corresponding service URI. This mediator eliminates the need for complex local look-up tables at the S-CSCF, improving scalability and ease of updating while maintaining routing functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If complex look-up tables are maintained for local TEL URI resolution, then routing accuracy is maintained, but updating difficulty increases

Engineering Contradiction:
Improverouting accuracyVSAvoidease of updating
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The DNS server autonomously manages the resolution of local TEL URIs to service URIs without requiring manual updates at the S-CSCF. When routing information needs to be updated, changes are made at the DNS server level, and the S-CSCF automatically retrieves updated information through DNS queries. This self-service mechanism maintains routing accuracy while dramatically improving ease of updating.

Inventive Principle:
Principle #25Self-service

3Productivity

If DNS lookup procedures are implemented for local TEL URI resolution, then scalability improves, but query string construction complexity increases

Engineering Contradiction:
Improveresolution efficiencyVSAvoidquery string construction
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent transforms the local TEL URI into a DNS query string by applying specific parameter changes: removing non-digit characters, reversing the digit sequence, and appending a domain suffix. This systematic transformation approach enables efficient DNS-based resolution while maintaining a relatively simple and automated query string construction process at the S-CSCF.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2070299B1Address resolution in a communication system
Publication Date: 2013.08.28 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2070299B1 patent drawingFigure 1~3
  • EP2070299B1 patent drawingFigure 2

AI summary

Apparatus for resolving a local TEL Uniform Resource Identifier to a service Uniform Resource Identifier for routing a message over an IP -based communication system. The apparatus comprises first processing means (2) for constructing a domain name system query string incorporating digits of the TEL Uniform Resource Identifier and a Context Identifier associated with the TEL Uniform Resource Identifier, and second processing means (3) for performing a Domain Name System lookup using said domain name system query string and for receiving in response said service Uniform Resource Identifier.