Plugging Into the Latest Developments on NGN and IMS Interoperability

By Michael Khalilian

In 2009, the forum continued with its interoperability programs, known as IMS/NGN Plugfests, and added new working groups focused on the control plane, IP/OSS/BSS, and the Diameter protocol and security. We published a number of technical guidelines papers related to these topics. And we have seen significant planning around NGN IMS deployments that have been mapped to NGN technology advances and changes in the industry since we held our first plugfest in 2007.

The IMS and NGN Forum held its eighth plugfest on Oct. 5 through Oct. 9, 2009, at the InterOperability Lab in Durham, N.H. While all of the results have not been tallied as of the time of this writing, it was a success by all accounts.

Plugfest 8 focused on interoperability for voice and multimedia applications, BSS/OSS and inter- and intra-network security including:

• end-to-end interoperability testing for IMS and NGN applications and services;

• interoperability of the control plane and the Diameter protocol; and

• charging function impacts on BSS.

Examples of test topics covered in Plugfest 8 included:

• multi-domain scenarios covering user-to-network and network-to-network IMS interoperability;

• application and feature testing across the control plane;

• billing interfaces;

• online and offline charging scenarios for IMS events and sessions;

• interface compliance testing (the 3GPP standard interfaces that use Diameter); and

• topology hiding scenarios (IMS/NGN control plane interoperability including border controllers, legacy network gateways, service location function and policy control elements).

We tested operations, and application management, NGN and IMS deployments, integration of network elements, OSS/BSS and security and QoS evaluations. Plugfest 8 participants and contributors included:

Comverse, HP, Mu Dynamics, NTT-AT, Radvision, Sonus, Tekelec, Tektronix, Testing Technologies, U.S. government communications agencies, Japan NICT (National Institute of Information and Communications Technology), Maben-Products, and others.

At Plugfest 8 we also held an initial planning meeting for Plugfest 9 and 10, to be held in 2010. The meeting included service providers

and integrators, applications developers as well as governmental research/agencies from the U.S. and Japan. Topics of importance to our members for future Plugfests in 2010 included the following:

• IPv6;

• IMS Rel.7 & 8;

• IPSec for UE;

• SIP signaling compression;

• IPsec using AKA;

• RCS testing (not to overlap with OMA testing);

• VCC single radio and access domains;

• triple play;

• OSS billing.

There also was significant interest in testing for 4G (LTE and WiMAX), femto, VCC and FMC. Defining the ROI for migration to convergence also was important. These are all topics that we will address in the coming year. In 2010 we will focus more on metrics, ROI and business cases and we will devote a working group just to that. Plugfests 9 and 10 will take place in the spring and fall of 2010.

Our plugfests have followed a logical path, becoming increasingly complex as the technology matures, as the following list of titles shows. We have held more NGN IMS interoperability events than any other forum in the industry.

Plugfest 1 – January 2007, “IMS Infrastructure”

Plugfest 2 – June 2007, “Voice and Multimedia”

Plugfest 3 – October 2007, “A Network of Services”

Plugfest 4 – February 2008, “Triple Play, OSS and Billing”

Plugfest 5 – June 2008, “Gm Interface, Load Balancing and Security”

Plugfest 6 – January 2009, “Robustness and Reliability”

Plugfest 7/8 – October 2009, “Home and Visiting Networks”

We are pleased to say that the progression of our series of plugfests to date has followed along with the plan set at the outset to be executed in phases. The phases are outlined below.

Phase I
Defining “reference” IMS test network

Non-stress testing and basic interoperability

Examine interaction of north/south interfaces

Phase II
Enhanced interoperability and interaction east/west

Nomadic services

Forward migration, moving from 2G to IMS

Presence services

Phase III
Focus on performance, scalability and load testing

Basic security (DOS attacks)

Electronic surveillance (CALEA requirements)

Phase IV
Security and support systems, advanced attacks

Enhanced security, support systems

Multiple types of IMS networks

We look forward to seeing what new advances our plugfests will bring in 2010. We welcome all of the telecom industry to get involved in helping us move the bar for NGN and IMS services.

NGN Michael Khalilian is chairman and president of the NGN Forum & IMS Forum (www.NGNForum.org / www.IMSForum.org).

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