1460 - Standards: IMS and Convergence Ready

Introduction

Session Border Controllers today provide critical functions such as firewall and NAT traversal, regulatory compliance, security, and QoS when launching VoIP and Multimedia services. This is however only one piece of the puzzle. Equally importantly, SBC deployments today must evolve to meet the future demands of convergence architectures such as IMS and TISPAN. In short, equipment purchased today must be IMS ready. Only if this approach is taken can an operator ensure that network investment is optimized.

Evolving Standards

The aim of any converged network is to allow rapid deployment of new services capable of being accessed from a variety of devices over a variety of access networks. The key to achieving this level of interoperability is the development of a set of standards covering access, i.e. what device is being connected, and service delivery, i.e. what services are available. The glue that sits between the devices and the service is the IMS - allowing any device to connect to any service.

Getting there is not a single step; 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 promises to deliver a broader coverage than its predecessor.

IMS was first defined by 3GPP and was designed specifically for mobile networks in its initial release. However this was seen as unnecessarily restrictive and subsequent releases of IMS have been defined to be access independent. This step promoted inter-working between different access devices and thus has stimulated the drive towards further convergence.

In the fixed-line world ETSI's TISPAN body (Telecoms & Internet converged Services & Protocols for Advanced Networks) is also working to standardize converged networks using IMS as its core architecture. The ultimate objective is to have a common IMS architecture for both fixed and mobile services by 2008/2009.

Work is also being carried out by the 3GPP2 (Third Generation Partnership Project 2) group; their Multimedia Domain (MMD) solution will allow CDMA2000-based access networks to provide third generation mobile services.

Newport Network 1460 and 310 in IMS and TISPAN architecture

Newport Networks product range sits at the border between IMS core and access networks, and between IMS Cores in the case of interconnect. In terms of IMS and TISPAN standards definitions, they perform the following:

These functions are deployed on a distributed architecture with the Newport Networks Border Controller providing the P-CSCF, PDF and IBCF. Newport Networks Border Gateway provides the BGF function. This is shown below:

Deployments in a Converged network require that the border controller and border gateway functionality adapt to the type of access networks to which they attach. For example DSL and WiFi Networks are insecure and do not have managed QoS. In addition they operate in IPv4 environments where overlapping address spaces are common place. These access types will require both a signalling proxy and media proxy to be deployed with QoS, Security and NAT/Firewall functions deployed. In the case of wireless 3G access, security at the transport layer and QoS for the media is provided by the wireless access network. Consequently these networks only require SIP security and an interface from the border controller to the access network to communicate quality requirements. No border gateway is required in this case.