IMS Roaming-Master thesis specification

Introduction/Technical area

The connection of mobile traffic between different operators is handled by specialized operators, GRX-operators. The connection is called roaming. There is now an ongoing development of a new service platform, IMS (IP multimedia subsystem) which also need the roaming feature. IMS is a service platform based on IP using SIP for signaling and RTP for media. It will be able to enhance the communication between mobile and fixed networks.


The aim of the thesis is to create and evaluate different alternatives on how to design and evolve a roaming system for the new IMS-based services. Today roaming partners are interconnected via the GRX-network specified by the GSM Association. In the future, the roaming shall also work for both fixed and mobile IMS users in a converged network scenario. Key issues include IP routing, DNS functionality and Security.

The thesis work will be system design based on specifications. In case needed there is a laboratory facility to test important properties using commercial routers.

Background information sources

The GSM-Association has proposed a specification for the handling of the roaming traffic. This specification is the base. Background information is

Knowledge of TCP/IP, DNS, routing is needed.

Reporting: A written report (English) and a presentation in audience shall be made.

Supervisors: Jonas Malmqvist, Sven Sjölinder

Other information

The working location is at Ericsson in Älvsjö; Product development unit IMS, IP Infrastructure. Two persons working together will be allocated to this thesis by Ericsson. It is open for any student to apply, one by one or in pair. The appropriate length is 5 months. Application, at latest 2005-12-16 is sent by mail to

last update: 2005.12.06