Cross Cluster Extension Mobility in IP Telephony

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Solution Overview

Problem

Existing IP telephony systems, such as Cisco's Extension Mobility, do not allow users to seamlessly traverse different clusters within a network, limiting mobility and access to personal telephony features across multiple clusters.

Innovation Solution

A method and system that supports Cross Cluster Extension Mobility (CCEM) by using an application server to perform extension mobility login and configure Trivial File Transfer Protocol (TFTP) service parameters across multiple clusters, enabling users to log in and access their personalized features from any IP telephony device within the enterprise network domain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Extension Mobility is implemented within a single CUCM cluster, then users can access their personal telephony features on any IP phone in that cluster, but users cannot traverse different clusters within the network

Engineering Contradiction:
Improvecross-cluster mobilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

An application server is introduced as an intermediary component between users and multiple CUCM clusters. The application server receives extension mobility requests from users, determines the appropriate home cluster, and coordinates with that cluster to establish the mobility session. This intermediary approach enables cross-cluster functionality without requiring complex modifications to each individual cluster's core architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system architecture is segmented into distinct functional components: the application server handles cross-cluster coordination and user authentication, while individual CUCM clusters maintain their existing extension mobility capabilities independently. This segmentation allows each cluster to remain relatively simple while the application server provides the complex cross-cluster orchestration.

Inventive Principle:
Principle #1Segmentation

2Productivity

If users are assigned dedicated desks, then they have consistent access to their work environment, but companies incur higher costs for office space

Engineering Contradiction:
Improveemployee productivityVSAvoidoffice space requirement
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The extension mobility system enables users to independently log onto any IP phone in the network using their credentials, automatically transferring their personal telephony profile to the device. This self-service capability eliminates the need for administrative intervention when users access different locations, making hot-desking and remote work practical while maintaining full access to personal features like speed dial, voicemail, and call forwarding.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2127228B1Method and system for supporting cross cluster extension mobility in internet-protocol telephony
Publication Date: 2018.04.04 CISCO TECHNOLOGY INC
  • EP2127228B1 patent drawingFigure 1
  • EP2127228B1 patent drawingFigure 2A
  • EP2127228B1 patent drawingFigure 2B

AI summary

A method to support cross cluster extension mobility (CCEM) in a communication network, which includes a plurality of clusters, each of the plurality of clusters including a call manager, the method includes receiving a request for cross cluster extension mobility from a user on a first telephony device located in a first cluster; adding a second telephony device in a home cluster for the user, only if the first cluster is different from the home cluster. The method further includes performing extension mobility login for the user on the first telephony device; and configuring A Trivial File Transfer Protocol (TFTP) service parameter of the call manager in the first cluster.