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Top Ten Considerations for a Successful Evolved Packet Core Deployment by Jon Morgan, Senior Director of Product Marketing       8/18/2009 The Evolved Packet Core (EPC) is the next generation multimedia core network for 4G access and is required to deploy LTE radio technology. It provides optimized access for 2G, 3G, non-3GPP and potentially even fixed access networks. Due to the sizable investment required to roll out LTE radio access, the wireless industry tends to lower the priority of the packet core, leaving the EPC exposed to mediocrity, last minute short cuts and a lack of standard-based IOTs -- just to name a few things. However, the business drivers of emerging LTE radio access impact the EPC as much including fast and efficient introduction of new multimedia services and applications, lower overall cost through intelligence and optimization, and session/subscriber management.  As you plan your LTE/EPC networks, here are the top 10 considerations to analyze when deciding your architecture, deployment strategy and vendors. #1.  An Open Evolved Packet Core The industry tends to couple the LTE radio (the E-UTRAN) and the Evolved Packet Core (EPC).  However, the EPC is being standardized as the core network for all access mechanisms, including: LTE, 2G, 3G, non-3GPP, and even wireline networks.   What is your rollout plan for integrating all of the access networks into the EPC? Are you considering how 2G, 3G, 4G, non-3GPP, and even fixed networks access the core, maintain seamless mobility, and obtain consistent and optimized services? The "open"EPC allows the operator to realize a truly converged packet core supporting all access technologies. The planning around the EPC must consider how all of these access networks enter the core, interwork with legacy systems, maintain seamless mobility and provide consistent and optimized services.  #2.  Deployment Flexibility and Network Optimization One of the key deployment considerations is the location of each of the EPC functions both initially and over time. Each operator has unique requirements and no one deployment model will suit all operators.  Which deployment model is optimal for your specific network requirements and how does it evolve from 3G over time? No one deployment model will suit all operators. Do you start with an overlay? Do you use a distributed or centralized architecture? Does the platform support integration of 2G, 3G and 4G functions? Are you considering Call Localization, Internet Offload and Local Breakout to minimize your operational cost? Does your existing 3G network support a seamless software upgrade to 4G functions? #3.  Control Plane Intelligence, Scalability and Signaling When looking at your packet core network as it evolves to LTE, have you considered the implications and limitations in the signaling portion of your existing network? LTE brings multiple challenges to signaling. With the flattening of the radio network, the Mobility Management Entity (MME) and Serving Gateway (SGW) are bound to have massive load of transactions per second. The elimination of a node equivalent to the RNC in the LTE radio network hierarchy increases the signaling requirements as the eNodeB's are connected directly to the MME. This means the MME will be handling significantly greater signaling loads than a typical SGSN including: paging requests to all eNodeBs, exposure to all inter eNodeB mobility events, in addition to NAS signaling ciphering and integrity protection.  What impact does LTE and interaction between 3G and 4G have on your control and bearer plane scalability? Have you looked at the impact of attaches, detaches and mobility management on your existing SGSN? Integration of SGSN and MME could save 30% on both elements. With the flattening of the network, the MME and SGW are bound to have massive load of transactions per second.  Is your MME a high transaction processing element with intelligence to minimize latency, provide paging optimizations, and leverage Self Organizing Network (SON) capabilities? #4.  Session-State and Subscriber Management While mobile networks use IP for transport, a mobile-enabled multimedia EPC is about subscriber and session management. The requirements for these networks are very different than existing IP transport-based networks that use traditional IP routers that are not designed and optimized for subscriber and session management.  Is the planning and selection of the EPC infrastructure considering all the implications of building a session state-aware, subscriber-aware, service-aware, access technology aware and location aware network?  Is the platform optimized for Layer 3-7 application/session routing or is it a transport plane platform? Does the solution support advanced flow-level interception? Does the solution support a scalable lawful interception? #5.  Policy and Charging Control with Integrated Intelligence Mobile operators are recognizing the unmistakable reality that bandwidth along with CAPEX and OPEX are increasing much faster than revenue. They must work to control skyrocketing bandwidth growth through network resource management as well as introduce next-generation personalized services such as live streaming video, games, rich content, music, IPTV, VoIP and video-enabled phone calling. These services involve differing levels of bandwidth, latency tolerance and data flow treatment. In addition, mobile operators are looking for solutions that monitor, observe and analyze network and traffic conditions in real-time, while having the intelligence to modify policies if required.  How is intelligence with policy and charging control (PCC) integrated into the complete solution? Does the solution meet 3GPP standards by integration the Policy and Charging Enforcement Function (PCEF) into the PGW? Does the solution provide services that enable you to monetize services and applications in the Mobile 2.0 world?  While the EPC is the smallest percentage of overall mobile operator wireless infrastructure spending, the EPC provides the greatest potential impact on overall network profitability through generation of new services and cost savings. This is accomplished through the creation of an intelligent EPC network, as opposed to a transport utility "bit pipe"network. Incremental investment in an intelligent 4G EPC allows mobile operators to monetize the network through service creation and lowering of the overall cost of the core and backhaul network. #6. Voice-Grade Reliability Mobile operators succeed when they deliver an experience that meets and exceeds the expectations of their subscribers. A key consideration to this success is, of course, the availability of the network and its services. The elements within the mobile network are the backbone of an operator's business.   How reliable is the overall network? Is geographic redundancy provided? Does the solution protect individual subscriber sessions or just IP flows?  Obviously, reliability translates into revenue savings, prevents revenue leakage and customer retention as lost service is lost revenue and customers. For example, many operators use external systems for billing to correlate usernames with IP addresses and billing information. If these products are not designed with stateful reliability, the end-to-end billing solution has lower reliability because of these "weak link"systems. This results in lost data and lost revenue.  #7. Security Mobile operators realize the importance of expanding service offerings to address the home, enterprise and hotspot markets. Due to LTE radio challenges, many operators are considering deploying radios in non-traditional locations, such as metro LTE radio deployments in buildings, on poles or other less secure areas. Finally, to lower the cost of deploying networks, many operators are considering sharing radio locations.  What are the security concerns in an all-IP 4G environment?  For example, how is access backhaul security provided? Does the security solution support multiple trusted and un-trusted applications? Does the security solution scale to large number of base-stations or home base stations? Does the solution support enterprise VPN functions such as L2TP, IPSec and Mobile IP? While security has always been a top priority in mobile networks, these emerging new access networks require even stronger security. 3GPP has standardized security as part of the EPC elements. 3GPP also defines the evolved Packet Data Gateway (ePDG) as the standard element responsible for interworking between the EPC and any unsecure access network, such as, wireline networks, Wireless LAN, femtocells and even shared access networks. The 3GPP standards, including the ePDG function, are based on IPSec/IKEv2 standards.    #8.  Reporting, Monitoring, Accounting and Charging Session, application and network knowledge are critical components necessary to provide a superior service experience to customers. This powerful information can be leveraged to provide a comprehensive consistent set of statistics and reports.  Do you have access to and can you leverage all the available session, application and network information in the EPC -- a Unified Service Management capability? Can the same information be leveraged to modify policies either manually or dynamically to provide a better service experience to the customer?  Am I able to collect real-time service information, including information from Layer 1 to 7 plus real time tracing and troubleshooting information?  How accurate and consolidated is the network's accounting and charging architecture? Do you have revenue leakage and don't even know about it? Does the accounting and charging solution allow mobile operators to monetize the full value of their network while offering a compelling range of services?  #9.  Roaming (GTP and PMIP6, DSMIP6, MIP4) In the standardization of LTE and the EPC, 3GPP specifies mobility protocols from both traditional 3GPP networks and non-3GPP networks -- GTP and PMIP6, DSMIP6, MIP4. The Mobile IP-based protocols will typically be used for connectivity to non-3GPP networks, such as, CDMA, WiFi and femtocell. The design of the EPC core must consider subscriber roaming both on to other LTE networks, as well as non-3GPP accesses. The selection of the core vendor must have expertise in both GTP and these mobile IP-based protocols, but also consideration must be made toward supporting both technologies within a single platform to minimize complexity and cost.  Are the EPC nodes ready to support all types of roaming arrangements? Is roaming supported between operators and between different technologies?  #10.  Multimedia Services One of the biggest disruptions in the mobile industry is the movement to an open, IP-based architecture designed to deliver converged voice, data and multimedia services. The emerging mobile packet technologies, HSPA and LTE, provide an all-IP infrastructure from the mobile device whether a handset, Smartphone, data card or other emerging intelligent device. With all-IP networks, the door is open to providing the traditional circuit-based services, including voice and video, over the packet infrastructure.  How do you migrate from circuit-based voice to packet voice and multimedia services? How do you migrate and deploy an infrastructure that enables services such as video, IPTV, presence, instant messaging and others? Does the solution support the evolution to an all-IP network with IMS with minimal impact on the overall network? How are you planning to support legacy interfaces required to support legacy circuit domain services such as SMS? Summary The deployment of LTE is another step in the evolution of the mobile broadband networks.  While the deployment of 4G radio access networks receives considerable attention, the multimedia core network has emerged as a critical element in the delivery of next generation mobile broadband services.  Since not all EPC networks are created equal and your goals with LTE/EPC are unique, addressing these and other challenges will help you work through the many aspects of evolving to and deploying the LTE/EPC network. About the Author Jonathan Morgan is senior director of product marketing for Starent Networks, a leading provider of infrastructure solutions that enable mobile operators to deliver multimedia services. About Starent Starent Networks, Corp. is a leading provider of infrastructure solutions that enable mobile operators to deliver multimedia services to their subscribers. Starent Networks has created solutions that provide mobile operators with the functions and services needed for access, mobility management and call control in their networks. Through integrated intelligence and high performance capabilities, Starent Networks' solutions also enhance subscriber management, billing and session policy enforcement. The company's products are capable of supporting a wide range of mobile wireless networks, such as CDMA2000, UMTS/HSPA, LTE, WiFi, and WiMAX. Starent Networks' products have been deployed by over 95 mobile operators in over 40 countries. See Our One Minute Videos   Contact Us to Present your Views Here Send us your response to this article. Learn How to Get Your Column Published on this Site