|Latin America 2005
|Next generation network evolution – finding the path
|Newport Networks Ltd
John Everard is the CEO and co-founder of Newport Networks. He previously held senior positions with Newbridge Networks, for over a decade, establishing Newbridge Information Systems before taking responsibility for its operations in Europe, Middle East and Africa. Before that, Mr Everard played a major role at Mitel, becoming Vice President and General Manager, EMEA. He has also served as Chairman of Telspec Ltd. Much of his early experience was gained at the British Telecommunications Research Department and Bell Northern Research in Ottawa, Canada. John Everard holds a BSc Honours degree from the City University, London, and an MSc from the University of Essex.
To face competition and meet customer needs, most operators will migrate to Next Generation Networks (NGNs). To protect their investments, they need flexible infrastructures that can evolve with the standards while meeting their immediate needs. The IMS (IP Multimedia Subsystem) standards are defining NGNs. IMS provides the flexibility to introduce the VoIP services operators need to generate the revenues during the migration to NGN, and customers will be rewarded by the introduction of an increasingly rich, accessible, range of services.
If you’ve been following the telecommunication press recently, you would be forgiven for thinking that IMS (IP Multimedia Subsystem) will revolutionise communications networks overnight and usher in a new era of ubiquitous multimedia services. In reality, standards and networks will evolve over a period of time to achieve this goal. Operators in Latin America are taking a pragmatic approach to the rollout of new infrastructure, to ensure that today’s deployments are IMS ready. This approach optimises an operator’s network investment. IMS permits service implementation, independent of access type, so that a single service can be delivered to a wide range of terminals. Consequently, services can be developed and delivered more quickly and delivered to a larger market. This reduces the operator’s risk and provides end-users with a greater range of competitively priced services. It is a win-win situation, but how do we get there? To answer that question we need to examine the operator’s needs, and what is driving the move towards Next Generation Networks. Today, there is a need to deploy simple, competitive VoIP services that will generate a sustained revenue stream and ensure the operator’s place in the competitive and evolving VoIP marketplace. At the same time standards are evolving to define the Next Generation Network (NGN), a huge undertaking in itself. First, let’s take a look what an operator needs today. Immediate operator needs Today, operators are addressing the immediate need to deploy VoIP (Voice over IP) and MoIP (Multimedia over IP) services to business and residential customers. This means dealing with problems such as service reach, service reliability, security and interconnection. Building an infrastructure that can deliver these capabilities is underway right now, with operators in Brazil and Mexico taking a slight lead with their IMS plans. The key to the long-term success of the new services will depend on the ability of the underlying infrastructure to adapt to the evolving IMS standards. Effective session control is at the heart of solving these issues. This has led to the widespread adoption of Session Border Controllers (SBCs) to provide solutions to these problems. SBCs typically consist of two primary functional elements, a signalling element and a media element, hosted within a single device. They handle the relationship between the separate signalling and media paths that characterise VoIP and MoIP calls. This enables them to address issues in both the access networks and the interconnection between networks. In an access network, SBCs increase service reach by allowing access to customers behind NAT or Network Address Translation, devices, thus increasing the potential subscriber base. SBCs can police the calls being admitted to the access network to prevent overbooking of resources and thus a loss of quality. Media can be policed to ensure it agrees with requested services to protect quality and prevent service theft. SBCs at network interconnect points help to secure the network by performing ‘topology hiding.’ This prevents the propagation of network and personal details and limits DoS (denial of service) attacks. They also provide valuable accounting data about the exchange of media, permitting more accurate inter-operator settlements. Regional regulatory requirements call for VoIP operators to provide emergency call handling and ‘Lawful Interception’ facilities. SBCs can deliver these functions. The SBC’s ability to deliver effective call/session control facilitates the creation of reliable, secure and compliant services in today’s VoIP networks. To develop networks that can migrate to IMS, it is essential that they be flexible enough to evolve with the standards. The success of IMS as a globally accepted architecture relies on standards development. Before examining IMS, let us look at some of the key organisations involved in their development. Evolving standards Converged networks allow rapid deployment of new services that can be accessed from a variety of devices over a variety of access networks. Access standards governing the devices being connected, services availability and service delivery are the key to extensive interoperability. The glue that sits between the devices and the service is the IMS that allows any device to connect to any service. It takes a series of steps, though, to get there. Bodies such as 3GPP (Third Generation Partnership Project) and ETSI (European Telecommunications Standards Institute) have phased releases of standards planned over the next few years. Each release provides broader coverage than its predecessor. IMS was initially defined by 3GPP specifically for mobile networks. However, this was considered restrictive, so IMS was subsequently defined to be access independent. This promoted inter-working between different access devices and has stimulated further convergence. In the fixed-line world, ETSI’s TISPAN body (Telecoms and Internet converged Services and Protocols for Advanced Networks) is working to standardise converged networks using IMS as its core architecture. The ultimate objective is a common IMS architecture for both fixed and mobile services by 2008/2009. The 3GPP2 (Third Generation Partnership Project 2) group’s Multimedia Domain (MMD) solution will standardise third generation mobile services for CDMA2000-based access networks. The standards bodies are drafting the roadmap for a journey that operators have already begun. Session control in the IMS Call Session Control Functions (CSCFs) are at the heart of the IMS ability to deliver ubiquitous services. The Proxy-CSCF (P-CSCF) handles the caller’s initial contact with IMS. It ensures that the user, if roaming, is registered with the correct network and that messages are correctly routed once registration has occurred. The P-CSCF detects which services should be hosted by the visitor’s network. This is important for routing content services, the provision of Emergency Call Handling and for Lawful Intercept. It can also provide defence against SIP signalling attacks. TISPAN also defines an Interconnect Border Control Function (IBCF) to formalise signalling interconnect between networks and Border Gateway Functions (BGF) to handle the media. IBCF functions include protecting and policing the signalling, topology hiding and conversion between IPv4 and IPv6 the new version of the Internet Protocol. It also controls a BGF that protects media exchanged across operator boundaries. Divide and evolve The session control functions of both today’s networks and IMS share some characteristics. An IMS core must provide the same physical separation of signalling and media elements now provided by SBCs. Accordingly, SBCs must be able to migrate from single nodes that handle both signalling and media to physically separated signalling and media nodes. Since functions within the converged networks and IMS definitions overlap considerably, it is important to consider each of the functional requirements throughout the network rather than defining products as a functional block. Today’s access network SBCs will be split to meet the signalling requirements of the P-CSCF and media requirements of the access BGF. Similarly, interconnect SBCs will be split to deliver both topology hiding and IBCF for signalling, and an interconnect BGF for the media. Operators looking to ride the next generation network, NGN, wave need a flexible infrastructure capable of evolving with the standards that meets their immediate needs and protects their investment. Standards are defining the capabilities and shape of NGNs. They will determine the evolution of session control elements, including SBCs, to support the separation of media and signalling functions. This provides the flexibility and independent scaling needed to introduce the VoIP services that will generate the revenues to carry the networks to the next generation. Customers will be rewarded through the introduction of an increasingly rich and accessible range of services.