Virtualization of the Evolved Packet Core (EPC) is a priority for many CSPs based on our research of ongoing proof of concept trials and early deployments of the technology. The economics of virtualizing the EPC makes sense to both optimize the network and scale out virtual network functions (VNFs) rapidly to meet the demand for new advanced services. However, virtualization of the EPC creates challenges using traditional measurement and monitoring tools. Physical probes which have been used for more than two decades to monitor critical links in the signaling and data session network are not suitable for assuring voice, video, and data services in the virtualized EPC. Incumbent suppliers such as Viavi Solutions and Spirent as well as newcomers like Affirmed Networks are introducing solutions into the market that support the dynamic movement of VNFs in the NFV/SDN network.
The level of investment activity in the mobile market is being driven by the fact that the mobile segment of the CSPs business continues to grow as other mature parts of the business are in decline. The evolved packet core network is an important technology domain for increased investments to support advanced services that will be launched into the market over the next 3 years. By consolidating multiple network functions on a single platform, the vEPC can operate more efficiently by performing tasks, such as deep packet inspection and metadata collection, only once in the network and sharing the results across the network.
The use of passive probing technology has been widely deployed over that past two decades. Physical tap points on links between network switches, gateways, subscriber servers (HLR), and authentication systems (AAA) served as the primary systems for test, troubleshooting, and assuring mobile network performance and service reliability. These same systems from suppliers such as Tektronix Communications, Netscout, Viavi (formerly JDSU), Spirent, Empirix, Anritsu, Polystar, Astellia, Qosmos, and others enabled CSPs to acquire a rich source of data used to improve operational support, planning new deployments, identifying customer care issues, and generate new revenue in marketing campaigns.
Telecommunication networks today use passive probing to tap critical links between network functions used to support both the packet and circuit switched network (figure 1). A dedicated purpose built appliance is used for passive probing of these links using T1/E1, 1G, 10G, and 100G uplink interfaces. Almost all suppliers of passive probing support mobile data and data center protocols (GN/Gi), LTE/EPC, and multimedia protocols (VoIP/IMS).
Traditional passive probe deployments have been very effective over the past two decades in both managing technology cycle upgrades and complex voice, video, and data services. Virtualization of the network and cloud based services will render physical passive probe technology obsolete.
The deployment of a virtualized network function (VNF) presents challenges in the traditional model of assuring services. VNFs will be instantiated based on resource demands. The VNFs and the links used to connect services will move dynamically based on utilization, policy, and business logic rules. As VNFs are added, moved, and de-commissioned the monitoring points must also be created, moved, and retired at the same rate.
Figure 2 shows a simplified view of the virtual Evolved Packet Core (vEPC). One or more functions will be instantiated on virtual machines (VMs) in one or more data centers which could span geographic regions. Many CSPs are actively employing a cap and grow strategy for the deployment of vEPC to take advantage of both the benefits achieved from lower capital expenditure and improvements in operational efficiency. The MME, SGW, and PGW are being virtualized. The use of virtual probes supplied by incumbent passive probe suppliers or suppliers of the vEPC will displace the dedicated physical probe appliance as shown in figure 4. Each instance of the virtual probe will be instantiated at the same time a VNF function is created or moved to assure a high quality of service.
The move from physical to virtual probe technology will follow a substitution pattern that we have seen with other technologies. During this transition where we estimate a substitution crossover to occur in 7 years, CSPs will operate in a hybrid network environment. This means that data will be collected from both physical and virtual passive probes to provide an end to end view of services and customer experiences across all technology domains.
For more information on our coverage of market developments in the assurance of NFV/SDN networks and the evolution of MANO policy management and closed loop analytics please contact me at

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