Telecommunication networks worldwide are undergoing dramatic changes address impending business challenges. Specifically wireline and wireless markets are undergoing convergence, which can allow communications anytime, anywhere, from any device; the combining of applications in new ways to deliver new services; or the consolidation of separate networks onto a common service layer.
Mobility markets are also evolving to take advantage of the new IP multimedia subsystem (IMS)-based services that are on the immediate horizon. Mobility networks are evolving to support not only connectivity to IP networks allowing mobile access to IMS-based applications, but also extending an IP connection out to the mobile device to provide end-to-end session initiated protocol (SIP)-based services and applications between the mobile device and IMS client. This is evident by the ongoing activities of mobility standards organizations such as 3GPP (the UMTS standards organization) and 3GPP2 (the CDMA2000 standards organization), which are defining standards-based IP architectures and interfaces for wireless networks. By evolving mobile networks to IP, new converged voice and data services can begin to appear, higher content voice and data services and integrated voice/data user devices can be enabled with VoIP.
The migration toward IP-based networks and services will require a core network infrastructure that is capable of distinguishing and carrying the different types of traffic by assigning appropriate class of service (CoS) parameters to ensure high-quality service delivery whether voice, data, audio or video. To that end, MPLS has emerged as the leading technology for providing the CoS required for today's telecom networks.
Core IP/MPLS networks provide the necessary infrastructure to support the migration towards IMS-based services and applications (VoIP, converged voice/data, audio, video, etc.). Additionally, IP/MPLS networks will be used to facilitate the transport of packetized legacy voice service over IP networks reducing associated transport costs, as well as provide for IP soft-handoff connectivity within and between mobile switching centers (MSCs). The primary requirement of these core IP networks is that they must be carrier grade and able to serve the differing traffic characteristics of a multiservice transport network.
The factors that make IP/MPLS well suited for carrier grade core networks are the following:
- Traffic engineering and optimization--Service providers can engineer MPLS LSPs to optimize network bandwidth. Directing traffic flow over specific core LSPs maximizes throughput, reduces congestion, and better utilizes the optical trunks between specific network switches.
- Service differentiation--IP/MPLS provides the ability to differentiate among services (voice, high-speed data, audio, video) in order to provide QoS as required by an application to ensure and enforce specific service level agreements (SLAs)/service guarantees.
- QoS for voice--Delay and packet loss have impact on voice quality as the packet core network introduces delays due to queuing, jitter and serialization delays.