Deploying Service Routers in an IP/MPLS Backbone for the Mobile CoreA P P L I C A T I O N N O T Ev Alcatel-Lucent|Deploying Service Routers in an IP/MPLS Backbone for the Mobile CoreTable of Contents1 Overview1 Introduction2 The Mobile Network Architecture3 Mobile NGN Drivers and Context4 NGN architecture5 The Rise of High-Value Data Services7 Solution Requirements8 The Alcatel-Lucent Solution for the Mobile Core Network9 High Availability Aspects11 Quality of Service and Traffic Engineering13 Network and Service Management13 Scalability of the IP Backbone for the Mobile Core14 Alcatel-Lucent Service Router Family Platform Descriptions14 The Alcatel-Lucent 7750 Service Router15 The Alcatel-Lucent 7710 Service Router16 Summary and Conclusions17 Acronyms1 Alcatel-Lucent|Deploying Service Routers in an IP/MPLS Backbone for the Mobile CoreOverviewUntil recently, the packet-switched core has been a best-effort adjunct to mobile networks supporting relatively simple, opportunistic applications. This is now changing; the strategicimportance of the IP/MPLS backbone for the mobile core is on the rise.Mobile operators are seeking to control costs and modernize their voice networks as legacyvoice switches move toward obsolescence. An important aspect of this evolution is next-generation networking using IP as a voice transportation vehicle in the mobile core. Manyoperators need to upgrade their best-effort packet-switched core as differentiated data servicesrise in importance, volume and diversity. In carrying out these initiatives, operators will wantto make investments that prepare an IMS infrastructure for the support of end-to-end IP-based services.The demands of NGN re-engineering, packet-switched core renewal and IMS infrastructureestablishment call for a new breed of IP/MPLS platform and a strong partner in networktransformation. Also, as Long Term Evolution (LTE) becomes an increasingly pragmaticoption for many mobile operators, Service Router-based network architectures will efficientlysupport this transition.This paper describes the emerging requirements and also the solutions based on the advancedAlcatel-Lucent service router family the Alcatel-Lucent 7750 Service Router and theAlcatel-Lucent 7710 Service Router. These platforms address these opportunities and positioncustomers for business success.IntroductionMobile service providers continue to see growth in subscriptions and especially in traffic levels.However, their operating margins are under pressure and successful service providers are con -tinually seeking strategies to reduce costs and offer new services to boost top line revenuesand customer loyalty. A correctly selected, engineered and deployed IP/multiprotocol labelswitching (MPLS) infrastructure can help service providers meet these objectives. Three phenomena or trends in mobile networks drive the principal requirements for theIP/MPLS infrastruc ture. The first of these next generation networking (NGN) isessentially the adaptation of voice traffic for converged transport over an IP/MPLS backbone.NGN brings strong potential benefits, primarily in OPEX and CAPEX reductions. Thesecond major trend is the shift of mobile data traffic characteristics carried by the IP/MPLSpacket-switched core (PS Core), from basic, best-effort, low-volume services to multimediabroadband and broadcast services. The third major trend is the deployment of the IP multi -media subsystem (IMS) to allow rapid deployment of end-to-end, IP-based services in an open environment. The Alcatel-Lucent service router family comprises IP/MPLS infrastructure products that canhelp service providers transition to an improved cost structure without sacrificing service quality.High availability, industry-leading network and service management, and powerful, service-oriented quality of service (QoS) make these platforms well suited to NGN architectures. Inaddition to delivering a solid solution for an NGN infrastructure, the service-oriented architectureof these platforms allows new revenue opportunities to be addressed effectively. Additionally,the platforms of the Alcatel-Lucent service router family can provide resilient, highly differ -entiated and secure IP/MPLS networking to underpin successful mobile carrier networksoffering innovative new services. 2 Alcatel-Lucent|Deploying Service Routers in an IP/MPLS Backbone for the Mobile CoreAlcatel-Lucent has significant and highly successful experience positioning these platforms in mobile networks worldwide. It has gained large-scale, end-to-end systems deploymentexperience in many IP-driven network transformations. And it has led the deployment of advanced wireline offerings such as triple play and IP television (IPTV).As mobile networks continue to transition to an IP-based multiservice environment, servicerouting and service-aware management will become even more compelling to mobile andconverged operators. The Alcatel-Lucent 7710 SR and the 7750 SR, together or separately,provide an optimized solution in the mobile core network infrastructure.The Mobile Network ArchitectureFigure 1 presents an abstract view of a mobile network architecture. It includes elements thatmay, in practice, be rolled out in successive waves of network evolution. The left side of Figure 1 shows the principal radio access network (RAN) mechanisms thatbring traffic to the mobile core. However, this document is concerned with the componentsshown on the right side of the illustration. In the circuit-switched core (CS Core), mobileswitching centers (MSCs) are the network elements that provide the switching of mobilevoice calls, traditionally via TDM point-to-point trunks. MSCs can also provide a gatewaycapability to the public switched telephone network (PSTN).As the CS Core is modernized, MSCs can be incrementally replaced by an NGN solutionconsisting of call servers (also known as softswitches or MSC servers), which support signalingand call control functions, and media gateways, which perform functions such as packetizationand compression on bearer channel traffic. This signaling and voice bearer traffic can now betransported between the call servers and media gateways, as appropriate, over the PS CoreIP/MPLS network. The PS Core has been in existence since 2.5G. It has typically consisted of a best-effort IP infrastructure overlaid with devices known as serving GPRS support nodes (SGSNs) and gateway GPRS support nodes (GGSNs). These devices implement subscriber trafficaggregation and tunneling, session management and access to the Internet.Figure 1. Overall Mobile Network ArchitectureInternetPSTNIMSCS CorePS Core(added at 2.5 G)SGSN GGSNCall ServerMGWMSCBTSBTSNodeBNodeB! , . ? ; :A 1 2 3 4 5 6 7 8 9 0@Q W S ZXE R T D F G C V WWW BY H J NUK L M * / - + = I O P > # % ) ( " ' ^