Next generation networks - design for reliability

The architecture of Next Generation Networks necessitates the adoption of new approaches to ensuring the reliability of these networks and the services they offer. The more distributed nature of network elements, as compared with legacy networks, can be advantageously exploited through the use of techniques such as continuous fault monitoring and automatic rerouting, leading to new approaches to recovery following equipment failure. NGNs have inherently different behaviours under overload and therefore also require new approaches to ensuring Quality and Grade of Service through, for example, appropriately managed packet classification and handling. Coupled with sophisticated server redundancy mechanisms and a layered approach to security, these techniques can be used to complement each other and ensure that NGNs can provide truly 'ReHlable Networks for Reliable Services'. I. NEXT GENERATION NETWORKS The accelerating deployment of Next Generation Networks (NGNs) represents a tipping point in the way communications services are delivered. As shown in Figure 1, a defining characteristic of such networks is that they are based around optical cores that carry Internet Protocol (IP) packets and provide connectivity independent of service. Services are no longer inextricably linked with separate infrastructures. Instead, they are the provided via computing servers linked to these common cores. NGNs also provide services that are independent of the access method that is used. Whether such access be fixed, mobile or via hotspots, it is simply the means by which end users connect to the packet core networks, and thereby access the servers and communicate with each other. The major service providers are now deploying their own distinct NGNs with carrier class capabilities. NGNs offer the potential of substantial cost savings to operators. They enable the delivery of innovative new services, with the potential for far greater control and personalisation by end users. Service innovation can be at the network edge, and therefore beyond the control of the network