HSS Password Push Mechanism for IMS Synchronization

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Solution Overview

Problem

In the IP Multimedia Subsystem (IMS) network, existing methods fail to efficiently manage password updates across network entities, leading to inconsistencies and performance overhead, particularly in SIP Digest authentication, where password changes may not be synchronized between the Home Subscriber Server (HSS), Serving Call State Control Function (S-CSCF), and User Equipment (UE).

Innovation Solution

A 'Push-Mechanism' is employed to update passwords using the Diameter protocol's Push-Profile-Request command, where the HSS generates or obtains a new password and transmits it to the S-CSCF, with both the new and previous passwords stored for authentication, ensuring seamless transition and minimizing network overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the S-CSCF periodically requests password updates from the HSS, then the password can be updated in the network, but this causes significant network performance overhead due to frequent message exchanges

Engineering Contradiction:

Improvepassword synchronizationVSAvoidnetwork performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of the S-CSCF periodically requesting password updates from the HSS, the invention inverts the approach by having the HSS proactively push password updates to the S-CSCF when changes occur. This eliminates unnecessary periodic requests and reduces network overhead while maintaining password synchronization.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The HSS autonomously detects when a password change occurs and initiates the update process to the S-CSCF without requiring external requests. This self-service mechanism ensures password synchronization happens automatically only when necessary, avoiding unnecessary network traffic.

Inventive Principle:

Principle #25Self-service

2Reliability

If the S-CSCF stores both new and previous passwords for authentication, then authentication reliability is improved, but the complexity of password management increases

Engineering Contradiction:

Improveauthentication reliabilityVSAvoidpassword management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The S-CSCF stores the previous password in advance before it becomes obsolete, allowing seamless transition during authentication. This preliminary storage of the old password ensures that users can authenticate smoothly during the transition period without service interruption, while the system automatically manages the complexity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP2040433B1Password update in a communication system

Publication Date: 2011.08.10 NOKIA SOLUTIONS & NETWORKS OY

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Figure 3

AI summary

The present invention relates to register entity (HSS) in an IP Multimedia Subsystem (IMS) that stores an identity of a user, maintains a password associated with the user and holds information about a serving entity (S-CSCF) currently assigned to serve the user. A new password for the user is obtained and the HSS replaces the old password with the new password in its database. The HSS transmits the new password to the S-CSCF assigned to serve the user, together with the identity of the user, when obtaining the new password.