White Paper Virtualisation in Telecoms Networks Intel® Architecture Processors Networking and Communications Realising the Benefits of Network Functions Virtualisation in Telecoms Networks

Executive Summary Network operators profit Network Functions Virtualisation (NFV) is a pervasive theme within the telecoms industry, from adding computing and over the past year, it has become a catalyst for major transformational change in the network. Many service providers, telecom equipment manufacturers (TEMs), and an power to the RAN and emerging NFV ecosystem have announced proof of concepts, live trials, and commercial core network. products embracing the NFV vision. In addition, forums such as the ETSI NFV Industry Specification Group and the Open Networking Forum have provided the necessary structures to support the initiative and its continuing momentum and evolution. Generally speaking, as more network functions are migrated to standard IT, high-volume server environments, the stronger the business case becomes for widely deploying cloud and IT data centre concepts in the telco network. From a service provider perspective, a major driver for NFV is OpEx savings; but additionally, NFV provides a platform for rapid service deployment and monetization, which is potentially even more important as it directly addresses growth models and revenue streams. For the TEM community, NFV facilitates the development of telecom solutions with application scalability in the cloud, optimized performance, software reuse, and increased use of open source software. Moreover, NFV is now becoming a key criterion in the vendor selection process. Service providers who have seen the benefits of NFV in concrete terms are requiring vendors to act as quickly as possible. Naturally, TEMs also see opportunities to win market share in this disruptive market environment. Opportunities exist for those willing to embrace the NFV dynamic, and the associated technologies and architectures necessary to make it a reality. However, many network functions have extreme characteristics that must be addressed by a highly-robust and scalable software and hardware architecture. Operators expect both telco-grade quality and equipment performance to improve or at least remain the same in an NFV environment. Consequently, TEMs must achieve high performance when running their applications on standard server hardware in the cloud. The LTE evolved packet core (EPC), and especially the gateway functionality, is a good example of an application requiring not only high-performance user plane, but also extended performance scalability in both signalling and control plane. The full benefit of NFV will ultimately be realised when mature reference architectures are available that facilitate easy deployment of disparate network workloads; deliver high performance, quality, and resilience; and can be intelligently managed to allow rapid service invocation and delivery. This paper is a joint effort by Intel, Qosmos*, and Tieto* to describe how standard IT, high-volume servers, and commercial and open source software can be used in a reference architecture vision to meet the challenges of network evolution, and thereby unleash the full potential of NFV. Realising the Benefits of Network Functions Virtualisation in Telecoms Networks

Table of Contents Reference Architecture Description 4. Maintain performance and resilience – Deliver high-performance packet Executive Summary...... 1 The reference architecture vision created processing and maintain system-level by Intel, Qosmos, and Tieto builds upon Reference Architecture Description. . . 2 resilience and quality. previous work that Intel and Tieto Network Functions Virtualisation developed and made available to the NFV 5. End-to-end orchestration and Infrastructure...... 2 community beginning in 2012.1 The latest automation – Demonstrate new evolution of the architecture is aligned services and software solutions that Virtualised Network Functions...... 3 to ETSI NFV ISG principles and has been can be quickly and effectively deployed NFV Management and Orchestration. . . 3 extended to address intelligent deep using automation (OpenStack* Heat), packet inspection (DPI), traffic shaping, and orchestration based on open Network Operation (OSS/BSS)...... 3 service invocation, and diameter signalling interfaces and OpenStack components, Cloud Platform...... 3 controller virtual functions. where functions are managed at the system level. SDN Networking...... 3 • The reference architecture is based on an Intel® architecture platform, The architecture consists of the following Application Cloudification Service which includes the Intel® Data Plane subsystems: Solutions...... 3 Development Kit (Intel® DPDK) and the Virtual Network Function as a Intel DPDK Accelerated Open vSwitch*. Network Functions Virtualisation Service (VNFaaS)...... 4 Infrastructure • Commercial grade components, including DPI Overview...... 4 Qosmos virtual DPI function, Tieto IP The NFV Infrastructure subsystem (TIP) Stack, Tieto’s virtualised Diameter provides the basis for a flexible, high- Business Benefits...... 4 Signaling Controller (DSC), and Wind performance, and highly-resilient Challenges to Overcome...... 4 River* Open Virtualisation Profile (OVP), virtualised telecoms platform. have been combined with example Addressing the Challenges...... 5 It includes standard IT, high-volume applications for virtual EPC and radio hardware based on the latest Intel® Virtualisation of the Mobile Core access (i.e., virtual base station) and architecture processors and Intel network Network (EPC) and IMS...... 7 integrated to showcase an end-to-end interface cards (NICs). The associated PoC proof-of-concept (PoC). Business Benefits...... 7 uses the HP* ProLiant* DL380p Gen8 The high level business and technical Server based on Intel® Xeon® processor Challenges to Overcome...... 7 objectives for the reference architecture E5-2690 (2.9 GHz) and Intel® 82599 10 Addressing the Challenges...... 7 (Figure 1) and the associated PoC are as Gigabit Ethernet Controllers. In addition, follows: there are several switches, including a Virtualisation of the Mobile Base high-capacity, OpenFlow*-enabled Intel® Station (in the RAN)...... 8 1. Faster innovation – Expand choices Ethernet Switch FM6764 (10 GbE/40 GbE beyond traditional manufacturers and Business Benefits...... 8 L2/L3/L4) and several 1 GbE switches that processor architectures to include open- are used for management interfaces. Challenges to Overcome...... 9 standard, open-platform ingredients, solutions, and services. The software execution environment is a Addressing the Challenges...... 9 Wind River* * distribution with Wind 2. Save costs – Decrease OpEx and CapEx Summary and Conclusions...... 10 River Open Virtualisation Profile providing by reducing dependency on proprietary virtualisation support, which includes hardware and providing virtualised KVM (Kernel-based Virtual Machine) and network functions on standard, high- OpenStack, as well as real-time extensions volume hardware, as well as through for virtualisation. of automated and simplified operation of load-based resource allocation, fault OpenFlow* provides SDN support by avoidance, and recovery. configuring an optimized version of Open vSwitch that takes advantage of SR- 3. Increase service revenue – Offer IOV (Single Root I/O Virtualisation) and software solutions and services the Intel DPDK2 to accelerate packet more quickly and easily via a flexible processing performance in a virtualised architecture that is well-suited for new environment. service creation and monetization. 2 Realising the Benefits of Network Functions Virtualisation in Telecoms Networks

Network Operation (OSS/BSS) and a Cloud Infrastructure Management NFV Management Interface (CIMI). The intent is to Map UI Cloud Manager and Orchestration demonstrate that a new VNF could be Orchestrator deployed and managed from an end-to- Virtualized Network Functions end perspective within the telecoms cloud, while also presenting necessary EMS EMS fault, configuration, accounting,

vBS vMME vGW vDSC vDPI performance, and security (FCAPS) Physical TIP TIP TIP TIP TIP information to the OSS/BSS complex. vBS Manager SDN Manager vEPC Manager Network vDSC Manager Functions Intel Intel Intel Intel Intel DPDK+ DPDK DPDK DPDK DPDK Cloud Platform VNF Manager(s) The Cloud Platform reference architecture Network Functions (NFV) Infrastructure Virtualized can be used to accelerate time to market Infrastructure Virtual Resources Managers(s) and deliver telco grade quality to NFV deployments. It is based on OpenStack Virtualization Layer elements that Tieto integrated and Linux* Distribution KVM+SR-IOV Neutron Suppliers: performance optimized, and includes Intel DPDK Accelerated Open vSwitch* Nova Intel telco-grade supervision, statistics, Keystone OpenStack* Hardware Resources diagnostics, fault, and performance OpenStack Glance Qosmos* Intel® Xeon® Processor management capabilities. ES-2600 Series-based Platform Tieto* NIC NIC SDN Networking Wind River* 10G/40G Intel® Ethernet Switch FM6764 SDN Agent Others The integrated SDN controller is compatible with the OpenStack Neutron + Intel® Data Plane Development Kit (Intel® DPDK) NIC: Intel® 82599 10 Gigabit Ethernet ControllerIntel® DPDK: Intel® Data Plane Development Kit and supports SDN networking and legacy Figure 1. Architecture Description network management system (NMS) integration, and provides supervision, Virtualised Network Functions that manages flow control to enable statistics, and performance management. intelligent networking. While the reference Virtual network functions (VNFs) are The OpenFlow protocol is used to architecture is orchestrator-agnostic, the deployed on the NFV Infrastructure. The communicate between the SDN controller PoC’s orchestration solution is provided PoC implements reference software for and the Open vSwitch, which is managed by OpenStack* and its subcomponents, LTE eNodeB and EPC (MME, SGW, and PDN by the OpenFlow controller. Efficiency including networking (Neutron), compute GW), along with Tieto’s Diameter Signalling is achieved via integration with the (Nova), and identity services (Keystone). Controller (DSC), which is deployed as orchestrator. The network management solution a VNF. To demonstrate intelligent DPI interfaces to Openstack (Heat) for Application Cloudification Service content inspection, Qosmos technology automation and deployment. Solutions is used, and the reference architecture Tieto development services for application allows it to be deployed either within a Network Operation (OSS/BSS) VNF or as a standalone virtual networking cloudification are available to help function component (VNFC). The Interworking with network operation companies accelerate time to market associated Element Management System requirements and legacy OSS/BSS3 poses and off-load their own R&D. The service (EMS) for each VNF is integrated within one of the biggest challenges for fast and decouples software from hardware or the VNF subsystem, which monitors the effective deployment of NFV applications decouples functions from the application, operational condition of the VNFs as in the network. The network operation enabling them to become cloud part of the overall Telecommunications subsystem comprehends the necessity applications and functions. The service Management Network (TMN). for standards-based integration of OSS/ optimizes the cost of cloud transition by BSS infrastructure as well as for overall taking into account the integration of the NFV Management and Orchestration management of the telecoms cloud. legacy equipment and the need for high To address these needs, the reference This subsystem manages overall VNF performance. architecture and PoC implementation deployment and lifecycle, and it also support a Netconf interface for OSS contains SDN controller functionality 3 Realising the Benefits of Network Functions Virtualisation in Telecoms Networks

ETSI NFV Use Cases and cyphered protocols, is inspected with signature upgrades. This is because PDN- fine granularity, which is possible with GW will require fewer upgrades, no longer While the reference architecture is the DPI capabilities provided by Qosmos needing bi-weekly protocol signature a generic, virtualised infrastructure virtual DPI module. Likewise, telcos are updates or the like. In addition, the designed to support different kinds of creating tiered data plans by using DPI PDN-GW function will have performance telecom workloads and applications, the technology to turn the core network into benefits without the burden of DPI associated PoC explicitly addresses the an application-aware system. processing that could be considerable radio access network (RAN) and the LTE when used intensively to generate more EPC. In addition, DPI is a key ingredient In NFV environments, alongside the QoS services revenue from mobile tiered technology that is supported in both the enablement, information generated by pricings, application charging, etc. architecture and the PoC. To demonstrate DPI can also enable telcos to optimize how the reference architecture supports costs through improved equipment Another way DPI can help monetize the key telecoms workloads, the following utilization while delivering on service level network is by helping to comply with sections describe three ETSI NFV use agreements (SLAs) to cloud consumers. specific regulations, public advocacy cases,4 detailing the challenges to be The Qosmos DPI function will present requests, or government laws by overcome and how the Intel/Qosmos/ extracted information to the orchestrator/ detecting questionable applications and Tieto reference architecture addresses analytics system, which triggers events web sites, thus enabling the PDN-GW to them. These ETSI NFV use cases are: such as scaling virtual machine (VM) take appropriate action. In such cases, the instances up or out. Virtualisation service providers may be able to upsell • Virtual Network Function as a Service technology offers the ability to relocate mobile services and increase average (VNFaaS) a virtual machine from one host to revenue per user (ARPU). • Virtualisation of the Mobile Core another without shutting it down, thus Network (EPC) and IMS The integration of DPI can also help telcos giving the opportunity to dynamically curtail increasing CapEx and OpEx costs by • Virtualisation of the Mobile Base Station optimize the placement with minimal enabling them to automate their network (in the RAN) impact on performance. Nevertheless, it scalability based on traffic patterns and is critical to be able to express application Virtual Network Function as a telemetry services. This supports the requirements related to VM placement industry movement driven by the ETSI Service (VNFaaS) and server state in order to define the NFV ISG to dynamically scale up and out Many service providers offer cloud VM placement constraints required to both the signalling (MME) and user plane computing services in addition to network model a viable configuration. For instance, (SGW, PGW). This is providing interesting services. Supporting both types of identifying which services are used and new possibilities to lower their OpEx costs services with common NFV infrastructure whether they are stateless or stateful is while controlling their CapEx thanks to requires resource pooling mechanisms necessary to ensure good performance. the relatively low cost of the underlying that allocate physical compute, network, commercial of-the-shelf (COTS) resources. The reference design provides guidance and storage resources to network on how to deploy such a VNFaaS, while in applications and VNFs.5 Once this is Challenges to Overcome parallel, optimizing the network topology achieved, it will be easier to deploy with a network-wide, VNF-based virtual VNF deployment: Separating DPI and individual instances of virtualised network base station and EPC solution. gateway functions, and managing DPI functions and offer them as services. within a SDN framework. Business Benefits The reference design demonstrates this DPI is playing an important role in new capability in its implementation of the The ability to deliver DPI as a VNF(C) will standards under consideration, such as ETSI VNFaaS use case by dividing the speed its deployment in the network, the Traffic Detection Function (TDF) VNFs into several instances that are resulting in quicker TCO savings, faster in 3GPP, and separating DPI from the deployable as-a-Service. service monetization, and a significant gateway function will provide telcos with improvement over existing core networks much more flexibility going forward. DPI Overview that only implement shallow packet Network elasticity: Scaling VNF DPI enables many functions in the core inspection (SPI). resources. network, including quality of service (QoS) In the case of the reference architecture, management through traffic shaping, In order to maximize the elasticity of network DPI is deployed as a separate VNF, throttling, and gating. In this case, resources, it is important to be able to scale enabling significant OpEx cost reductions network traffic, especially obfuscated network resources assigned to a virtualised associated with PDN-GW protocol network function both up and down. 4 Realising the Benefits of Network Functions Virtualisation in Telecoms Networks

Efficient dynamic scaling of virtual resources is essential for achieving the elasticity required from a virtualised OSS (SLA, SA) Analytics 3 telecom network. Scalability will also 2 Subs Data (CDRs, IPDRs) enable the flexible allocation of different OpenStack/Controller network functions based on actual traffic patterns, thereby reducing the need to Extracted Network overprovision network infrastructure. Information 2 vMME vPDN/GW vDPI Performance bottlenecks: Achieving Access Node Access performance on standard server hardware Access Node NFV Infrastructure and minimizing the overhead inherent in Node virtualised systems. Mixed IP Traffic 1 A challenge for this use case is to dynamically scale the DPI instances in Figure 2a. Extracted Information Triggers a Network Event relation to the virtual PDN-GW without dropping packets and ensuring existing DPI instances continue to properly classify OSS (SLA, SA) all the traffic. One hurdle is overcoming Analytics 4 the associated performance bottlenecks, Subs Data (CDRs, IPDRs) especially those related to inter-VM OpenStack/Controller communications. Scale Out To enable high performance transport, 5 Tieto IP stack (TIP) is used together with vMME Scale Up the Intel DPDK. vMME vMME vPDN/GW vDPI Access Addressing the Challenges Node Access Access Node NFV Infrastructure Node VNF deployment Mixed IP Figure 2 depicts the use case where Traffic the virtual DPI sends some monitoring information to the NFVI/SDN managers to Figure 2b. Extracted Information Triggers a Network Event optimize resource deployment. In Figure 2a, the virtual DPI function In Figure 2b, the data processing triggers Network Elasticity provides metadata information to a network event: The reference design employs cloud the management system in the SDN 4. The management system processes orchestration to automate the orchestrator: all the data, and based on the results, management of virtual resources using a 1. DPI is deployed onto the NFV adapts the network topology and high-availability framework, abstracted Infrastructure (Tieto IP Stack + Intel instances. service availability, automatic scaling of DPDK + Intel DPDK Accelerated network functions, and programmable 5. Based on the result, the management OpenvSwitch), and it monitors the traffic such as OpenFlow. Orchestration system triggers an update in the access using a promiscuous mode (SPAN). is implemented according to the NFV node network paths and scales up and framework, which requires support 2. The management system receives out the VMs accordingly. for dynamic and automatic resource monitoring information computed by the The end result is a DPI VNF(C) becomes allocation. vDPI, and correlates it with information a service in the NFV infrastructure that received from the OSS and CDR/IPDRs. The solution provides the means to provides network traffic information to satisfy service availability requirements 3. The management system processes the orchestrator. by efficiently scaling virtual network the data. functions – up and down – based on the load on the system. When a predefined 5 Realising the Benefits of Network Functions Virtualisation in Telecoms Networks

threshold is reached, automatic scaling is initiated. Additional CPU cores and DPI VNF Traffic PDN-Gateway Flow Classification Detection VMs are commissioned as traffic volume Guests and Metadata Extensions increases, and are later scaled back as Function (TDF) traffic decreases. Packet + Tag Packet + Tag I/O • Cloud management Host The reference architecture is built on the Tieto Cloud platform reference design, which: Traffic • Enables faster time-to-market (TTM) of Figure 3. DPI Implemented as a Virtual Network Function cloud-based solutions by accelerating product development. protocol capabilities to help optimize the Figure 3 shows a telecom infrastructure network, perform overload control and platform with DPI implemented as a VNF • Delivers solution accelerators, including load balancing, and implement topology component seamlessly interfaced with the means to manage any OpenStack- hiding to protect VNFs, thus allowing a virtual PDN-Gateway and a traffic based cloud. VNFs to scale in a controlled way. detection function (TDF). Operators can • Solves telecom-specific problems, like scale DPI capacity using orchestration to automated deployment, monitoring, In the reference architecture, load launch and retire virtual DPI instances, as and recovery of very complex balancing is explored from two different needed, to support business offerings like applications. angles: a virtualised Tieto Diameter tiered mobile plans, application charging, Signaling Controller ensures controlled freemium and premium plans, etc. • VM auto-scaling Diameter signaling distribution in the cloud environment while Tieto IP stack provides This feature automatically scales VM Performance bottlenecks high-performance IP load balancing. resources according to system load, One way to avoid performance creating new VM instances (similar to the • Virtual DPI scaling bottlenecks due to delays caused by existing ones) when the load exceeds a inter-VM communications is to deploy predefined limit, and retiring VMs when The reference architecture decouples DPI in front of incoming traffic (i.e., fast the load decreases substantially. the virtual PDN-GW and virtual DPI, path) as an active node with an integrated which simplifies the mechanism for tagging mechanism.6 Once the traffic/ • Load balancing and control signaling scaling DPI instances. As explained flows are classified, the DPI VM tags the previously, operators offering tiered Many 3GPP and IETF defined control packet headers to convey the protocol and pricing, freemium plans, and customized signaling protocols, such as Diameter, application-ID to the other nodes, like the Apps may rely on the DPI processing are by nature point to point protocols. PDN-gateway. This approach eliminates to classify and recognize specific The dynamic use of resources and the the need for VM to VM (networking applications used by mobile plan ability to scale/downscale VNFs must node to DPI VM) communications that subscribers. The ability to scale DPI be performed without impact on control can create delay and require significant capacity without impacting the virtual signaling between EPC/IMS nodes, as processing and bandwidth. When required, PDN-GW can lower security risks while in scaling the HSS shall not require the orchestration stack will scale up or out simplifying the networking management reconfiguration changes of the MME. the DPI VM instance independently of the of the virtual PDN-GW layer. Some 3GPP interfaces (e.g., Diameter other networking VMs. Gx and Gy) have user sessions, which Each virtual DPI instance may be Another advantage of this approach is it are not only identified by the point to configured to extract metadata from a allows flow management to be integrated point connection, but also with logical subset of a wide range of applications. at the DPI VM level, thus allowing the other information in the Diameter protocol. For instance, operators wishing to networking nodes (PDN-GW, TDF, etc.) to be When scaling a VNF, it must be assured classify 100 specific apps at 40 Gbps stateless, which simplifies their design. that user sessions are also maintained. and within a particular latency window will need the orchestrator to provide the The Tieto IP (TIP) Stack offers best-in- Diameter-enabled VNF nodes require corresponding VM with enough virtual class transport and packet processing Diameter Signaling Controllers (DSC) CPUs and RAM to meet performance solution designed to ensure high- that take maximal advantage of requirements. performance networks and reduce time 6 Realising the Benefits of Network Functions Virtualisation in Telecoms Networks

to market for equipment manufacturers. efficient allocation of network resources, control plane performance is needed to Well-suited for both slow and fast path and increased speed of innovation via deliver an acceptable level of service designs, the solution includes a Linux user efficient deployment of new services. and ensure the availability of regulatory space IP stack that is fully-featured and When increasing capacity or deploying services, such as emergency calls. telecom-grade, and is integrated with the new services, operators can add software- Intel DPDK. Applications can use either the based services to an existing virtualised Addressing the Challenges defacto socket API or an optimized zero- environment, instead of having to install a Service awareness copy API for improved performance. new network node. This will save time and money. Virtualisation also creates OpEx The reference architecture analyzes Virtualisation of the Mobile Core reduction opportunities, such as lowering packet flows and facilitates intelligent Network (EPC) and IMS power consumption during off-peak times traffic steering and service invocation by integrating DPI content inspection For this use case, the ETSI NFV using power management features to software into the virtualised specification provides a description and a power down unneeded portions of the infrastructure. The DPI engine, which list of high-level challenges related to the hardware platform. scales cost-effectively across large virtualisation of the mobile packet core Challenges to Overcome deployments, is a powerful tool for (i.e., the core network of an LTE system) creating service awareness and ensuring and IP Multimedia Subsystems (IMS), an Service awareness: Allocating resources service availability. The reference architectural framework for delivering IP to network functions based on the architecture also demonstrates how DPI multimedia services. services they support. content inspection enables performance Evolved Packet Core (EPC) Overview Virtual resource monitoring and optimization in the core network by orchestration, along with service making it service aware. The reference architecture demonstrates awareness, are essential for implementing how mobile core network functions can be elasticity effectively. Service availability virtualised on standard Intel architecture The use of standard server hardware and servers using open standards while Service availability: Achieving the same virtualisation technologies may introduce achieving carrier-grade service quality level of service availability for an end- performance penalties (i.e., interrupt and capabilities. Network functions (MME, to-end virtualised mobile core network servicing and context switching) that in turn P-GW, S-GW, and DSC) are deployed on the as in non-virtualised networks, but with could affect the level of service availability. NFV infrastructure (Figure 4). The main reduced cost. Therefore, maximizing performance and solution ingredients addressing the key Due to the nature of telecom networks, minimizing latency are critical success challenges are described in more detail in service availability will be a key issue factors, which can be addressed with the following. for a virtualised mobile core network. available technologies such as intelligent Business Benefits Since virtualisation usually leads to load balancing, DPI, and high-speed packet a performance trade-off, equipment processing. In the case of the reference Virtualisation of the mobile core network developers must take measures to architecture, user plane performance and IMS enables several advantages optimize data plane processing in order in virtual LTE gateways and eNodeBs is for service providers. Among the most to satisfy carrier-grade bandwidth and improved using the Tieto high-performance important are significant TCO savings, latency requirements. Similarly, sufficient IP Stack, SR-IOV, and the Intel DPDK.

Virtualized Base Station and Evolved Packet Core (vEPC) • Failure scenarios and high availability A telecom cloud has more stringent service availably requirements than EMS EMS an IT cloud, which can be addressed by virtualised infrastructure capabilities, such as placing VMs in high-availability vBS vMME vGW vDPI vDSC configurations (2N or N+1) and pinning VMs to specific CPU cores. The reference architecture was also designed to avoid single points of failure, supported by the Figure 4. Virtualised Base Station and Evolved Packet Core (vEPC) OpenStack-based cloud infrastructure.

7 Realising the Benefits of Network Functions Virtualisation in Telecoms Networks

• Carrier-grade VM Virtual BS Cluster Virtual BS Cluster Virtual BS Cluster Virtual machine (VM) failover allows a system to recover from a poorly functioning VM by moving its workload L1/L2/L3 L1/L2/L3 L1/L2/L3 L1/L2/L3 L1/L2/L3 L1/L2/L3 to a standby VM, which contains a clean

software image and is ready to be Load Balancer Load Balancer activated. This feature takes advantage & Switch & Switch of load balancing mechanisms for diverting workloads, but it also ensures the data stays current for both the active VM and its standby VM. RRU RRU RRU RRU Failover solutions must also identify VM state changes and trigger policy actions in the system. A change in VM state could RRU RRU RRU be spontaneous, as when a VM is killed, or planned, as when the cloud administrator manually changes it. Figure 5. Pool of Virtual Bases Stations and Remote Radio Heads Each virtualised application typically has a Today, the NFV vision is being applied Virtualisation of a base station node template that defines which state changes to the RAN, yielding benefits from allows functionality to run on standard are relevant for that application and the virtualisation; however, there are some servers, storages, and switches, enabling policy actions to be taken for each defined challenges that still need to be addressed resource sharing with other network state change. Currently, the policy actions to enable a virtualised RAN. functions, including third-party network supported by the reference architecture functions. Virtualisation creates a Business Benefits are restart the virtual machine; apply the competitive environment for vendors scalability policy to start a new VM for A node in the RAN traditionally serves a supplying innovative network functions up-scaling; and stop a VM for downscaling. limited geographical area and is typically that unlock the traditional proprietary The reference architecture supports provisioned for the maximum usage boundaries of RAN nodes. several failure scenarios, including VM, expected in that area, even though the In some cases, it may be possible to co- host, and network failure. It is also Service average load is usually far less. As a locate virtual base stations and virtualised Availability Forum compliant (see www. result, RAN nodes are often underutilized, evolved packet cores (vEPCs) in the data saforum.org) such that middleware (e.g., and today a RAN node cannot share its centre, enabling operations, administration, OpenSAF) can run within the VM to resources with other nodes. and management (OAM) savings. The protect the application within the VM. The pooling of base station nodes (Figure feasibility of this deployment approach may hinge on front-haul network lengths and Virtualisation of the Mobile Base 5) over a large geographical area allows the associated propagation delays. Station (in the RAN) network operators to more precisely dimension capacity and avoid bottlenecks A virtualised server platform close to the Containing a large number of nodes, the in an area served by multiple nodes, thus edge can host services, such as content radio access network (RAN) constitutes improving equipment utilization by sharing caching. Not only does this provide an a major share of the TCO and energy resources in the pool. opportunity for network operators to consumption in mobile networks. In large deploy revenue-generating services at the mobile operators’ networks, multiple RAN Base station (BS) virtualisation can access edge, users will also benefit from nodes from various vendors are usually achieve resource sharing among multiple improved performance. operated with different mobile network logical RAN nodes from different systems, systems (e.g., 3G, LTE, and WiMAX*) in the dynamically allocating the resource as well same area. It is possible to consolidate as reducing power consumption. BS is a these platforms into a virtualised base generic term referring to 2G BS, 3G Node 5 station (BS) using IT virtualisation B, and 4G eNodeB. technologies.5

8 Realising the Benefits of Network Functions Virtualisation in Telecoms Networks

Challenges to Overcome and software is decoupled, which further The overhead from VM enters and exits introduces challenges in management can become substantial since it is not Challenges that need to be addressed of the network. In addition, the network uncommon for I/O-intensive applications, include: operation needs to be able to handle such as base stations, to have hundreds Real-time performance: Upholding the the coexistence of legacy base stations or thousands of interrupts arriving in strict requirements of delay and jitter. with virtualised base stations that must a second. Similarly, a KVM guest may be combined with the large number of need to take thousands of VM exits per Virtualisation of the base station existing nodes in the RAN. second because of the internal timer introduces new sources of delay and jitter interrupt. These constant disruptions that must be minimized in order to maintain Addressing the Challenges cannot be tolerated with communications adequate service in the radio access applications because of the resulting network. These sources of delay and jitter Real-time performance degradation in performance, latency, and need to be included in the total delay It is possible to achieve near-real-time determinism. budget, from the base station to the radio performance in virtualised environments interface, together with other sources not when several main issues are addressed. The use of standard server hardware related to virtualisation, such as front-haul Foremost, it is necessary to minimize and virtualisation technologies will delays. Note that the front-haul challenges the interrupt latency and the overhead typically introduce performance penalties related to centralized deployment are not associated with virtualised, standard (i.e., interrupt servicing and context addressed in this paper. servers. A major source of performance switching) that in turn could affect the level of service availability. The reference Network elasticity: Optimizing the loss is from VM enters and exits, which architecture mitigates these penalties in a utilization of network resources by scaling typically occur when the hypervisor must number of ways, including: the capacity of the virtualised base service an interrupt or handle a special station in run-time. event. These transitions are expensive 1) The Tieto high-performance IP (TIP) operations because execution contexts stack implements SR-IOV (Single Root The virtualised base station must scale to must be saved and retrieved, and during I/O Virtualisation) in order to eliminate handle the network load and respond to this time the VM is stalled. the hypervisor’s involvement in data changing demands of service and capacity. movement by providing independent At the same time, it needs to minimize the memory space, interrupts, and DMA power consumption of the radio access streams for each VM. network. Even when the load is low and the virtualised base station is consolidated RTT Latency = Latency of 4 times through the stack to a few virtual machines, capacity needs must be met to ensure service fulfilment. 70 Polled Network management: Decoupling 60 management of infrastructure and Power Management+One-Shot IRQ network services in a multi-vendor 50 Round-Trip Time: environment with both physical network 40 functions and virtualised network Application Application functions with geographical and topology 30 Tieto* IP Stack Tieto* IP Stack Distribution (%) Distribution limitations. Intel DPDK+ Intel DPDK+ 20 The base station includes both virtualised and physical components, such as physical 10 remote radio units, which are tightly interconnected, limiting the flexibility of 0 deployment. The base station is part of a dynamic network in a constantly-changing 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90 90-100 100-110 110-120 environment with VM instances that Latency (us) Latency for ingress+egress stack transition: ~15us come and go based on load. Hardware Latency for ingress+egress stack transition, w. power management: ~20us +Intel® Data Plane Development Kit (Intel® DPDK)

Figure 6. Latency distribution of GTP-U traffic when testing 1) without power management in a purely polled setup and 2) in a setup with power management and the one-shot interrupt feature (based on an Intel® Xeon® Processor E5-2600 @ 3.4GHz). 9 Realising the Benefits of Network Functions Virtualisation in Telecoms Networks

2) The Intel DPDK enables Intel processor is implemented according to the NFV Summary and Conclusions cores to process packets continuously framework, and supports the required This paper describes how the reference without being interrupted by the dynamic and automatic resource architecture developed by Intel, Qosmos, operating system, other applications, allocation. and Tieto facilitates the deployment of or interrupts, which greatly increases The solution provides the means to satisfy NFV in telecoms networks and creates performance and determinism. elasticity requirements by efficiently opportunities for telecom equipment 3) Core pinning guarantees that a scaling number of VMs (up/down) in the manufacturers to fulfil the vision for particular flow, as identified by a five- virtualised base station based on the load mobile service providers. Designed in tuple (e.g., IP address, port and protocol in the covered area. When a predefined accordance with ETSI NFV ISG principles, type) or some other predetermined threshold is reached, automatic scaling the reference architecture addresses key criteria, is always sent to the same VM is initiated. Additional CPU cores and barriers to NFV adoption, and provides the for processing. This eliminates the need VMs are commissioned as traffic volume flexibility and inherent intelligence needed for sharing connection and forwarding increases, and are later scaled back as to unleash innovation and rapid service information among VMs because each traffic decreases. Off-loading cells are development and monetization. VM only needs to know about its own automatically commissioned as traffic The industry is in the midst of connections. volume increases in hot-spots. These transformational change, and industry off-loading cells are deactivated as traffic These approaches, along with others, help players who are proactively embracing decreases in the hot-spot areas. the TIP stack to process network traffic these changes will likely be the ones with 15 to 20 microsecond latency. Figure Network management to reap the benefits in the future. A 6 models the round trip time (RTT) from collaborative approach between service an external virtualised application to the The reference architecture integrates providers, network equipment providers, virtualised base station application and back. Tieto’s O&M framework for embedded silicon vendors, and independent software O&M in network functions, VNF managers, vendors (ISVs) is vital for accelerating Network elasticity and element management systems. telecoms network evolution, where the The O&M framework provides a flexible The reference architecture addresses benefits described in this paper can be solution that is easy to maintain and the challenge of network elasticity in the realised by all. extend, making it possible to tailor to RAN, enabling run-time scaling of the specific needs and requirements. The base station from a few virtual machines embedded O&M framework easily scales to utilizing the complete virtualised pool, network functions to meet a wide range based on the load within the covered area. of needs, from systems with a small The virtualised base station’s different memory foot-print to high-performance components are deployed in virtual EMS. The reference architecture machines implemented with a high- addresses SDN/NFV concepts and availability framework and automatic interfaces, for example decoupling of the scaling. It uses cloud orchestration to infrastructure and the network functions automate the management of virtual as well as integration with legacy systems. resources. The reference architecture

For more information about Tieto, visit www.tieto.com/pds. For information about Tieto components used in the reference architecture, visit www.tieto.com/signaling and www.tieto.com/tip. For more information about Intel® solutions for Telecoms, visit www.intel.com/go/commsinfrastructure.

For more information about Qosmos, visit www.qosmos.com.

1 See previous Intel and Tieto work at www.intel.com/go/commsinfrastructure and www.tieto.com/product-development/communications-infrastructure/tieto-carrier-cloud-network-equipment- providers. 2 For more detailed information about the Intel® Data Plane Development Kit (Intel® DPDK), see: www.intel.com/go/dpdk. 3 Operations Support System (OSS) and Business Support System (BSS). 4 See: http://www.etsi.org/technologies-clusters/technologies/nfv/nfv-poc. 5 ETSI GS NFV 001 V1.1.1 Network Functions Virtualisation (NFV): Use Cases www.etsi.org/deliver/etsi_gs/NFV/001_099/001/01.01.01_60/gs_NFV001v010101p.pdf. 6 Several initiatives are being drafted in the IETF Service Function Chaining (SFC) working group. Copyright © 2014 Intel Corporation. All rights reserved. Intel, the Intel logo and Intel Core are trademarks of Intel Corporation in the U.S. and other countries. *Other names and brands may be claimed as the property of others. Printed in USA 0214/MS/SD/PDF Please Recycle 330181-001US