Software Defined Networking (SDN) and Network Functions Virtualization (NFV) promise carriers significant savings in operational expense (Opex) and capital expense (Capex). The key challenge for the industry is delivering these promised savings without slowing network performance or reducing network resiliency. Carrier grade systems with high availability features provide an ideal platform for telecom equipment providers and carriers moving towards carrier grade SDN and NFV.


In this blog I am going to explore the benefits of using carrier grade ATCA-based systems with Intel® Xeon® processors to support the shift to SDN and NFV in carrier networks. For this blog I am using implementation examples from Radisys, an Associate member of the Intel® Intelligent Systems Alliance. The 250-plus members of the Alliance collaborate closely with Intel® to create hardware, software, tools, and services to help speed intelligent systems  to market.


Software Defined Networking and Network Functions Virtualization


Software Defined Networking (SDN) is designed to separate the data plane and control functions. This has the dual benefit of flattening the data plane and reducing latency, and increasing the flexibility of the control plane. A key feature of SDN is the use of open interfaces between the controllers and the networking elements including switches, servers, network appliances, media gateways and other network systems.

Intel- SDN Diagram.jpg

Figure 1. Software Defined Networking (Source: Intel)


Figure 1 shows the SDN architecture. OpenFlow provides an open protocol for Controllers to program the flow table in the switches and other networking systems. The switches use the flow tables to forward packets across the network. The SDN architecture can be expanded to cover wireless networking infrastructure including the enhanced packet core (EPC) and cloud radio access network (C-RAN). For large-scale cloud deployments the network can be managed through a cloud operating system such as OpenStack that controls large pools of compute, storage, and networking.


Network Functions Virtualisation (NFV), being developed within ETSI, enables a virtualized network infrastructure that can be quickly scaled and provisioned to support new services and additional capacity as required. NFV aims to replace fixed function systems with virtualized functions running on standard server systems. Initial implementations of NFV will support control plane functions such as policy management, serving gateway (S-GW), mobility management entity (MMA) and home subscriber server (HSS).


Carrier Grade SDN and NFV

Both SDN and NFV are relatively easy to implement in proof-of-concept environments. SDN and NFV are much more difficult to implement in carrier networks where five 9’s availability and wire speed packet throughput are critical business requirements.  In these environments latency and geographic distribution are important factors in determining the practical implementation.


Carrier grade systems use a mixture of processors designed for embedded server systems, such as the Intel® Xeon® Processors E5-2600 and E5-2400 Series, and packet processing acceleration for a range of functions including encryption, compression, load balancing and I/O pre-processing. The packet processing acceleration may be implemented on a processor chipset such as the Intel® Communications Chipset 89xx Series, on Network Interfaces Cards (NICs) or on a separate blade in the system.


Using ATCA for SDN and NFV


ATCA is a very flexible carrier grade platform that supports all the building blocks necessary to implement carrier grade SDN and NFV. Figure 2 shows a typical ATCA platform. There are two central switch cards that support 40Gbit/s switching to each of the 12 node blades. The node blades can be all processing blades or a mixture of processing, storage, DSP and network interface blades with network processors or other packet processing devices.



Figure 2. 40Gbps ATCA Platform


Figure 3 shows a typical Sandy Bridge ATCA blade with dual 8-core Intel® Xeon® Processors E5-2448L and up to 96GB DDR3 memory. The blade has dual 40Gbit/s interfaces connected over the backplane to the two switch blades. Similar blades are available from several vendors giving multiple configuration options and a strong supply ecosystem.


Figure 3. Sandy Bridge ATCA Blade.


In a typical ATCA-based SDN system the Sandy Bridge ATCA blades are used to implement the SDN control plane functions. The data plane is implemented on a combination of the integrated switch blades, DSP blades and network processor-based network interface blades. The network interface blades can be used for load balancing and packet preprocessing. The control plane and data plane are kept separate within the ATCA platform by using virtual LANs (VLANs).


The ATCA platform is already being used for many systems including the IP Multimedia Subsystem (IMS) Media Resource Function (MRF). The shift from 10Gbit/s to 40Gbit/s switching and the introduction of the latest Intel® Xeon® Processors and has significantly reduced number of blades required for a typical system. By virtualizing the MRF function Radisys has been able to develop a smaller implementation that can share an ATCA platform with other functions, significantly reducing the real estate and cost of the total solution.


A Staged Approach to Carrier Grade SDN and NFV


SDN and NFV promise significant Capex and Opex savings to carriers. By using a staged approach to implementing carrier grade SDN and NFV, carriers and telecom equipment providers can take advantage of existing carrier grade solutions, such as ATCA, to quickly deliver the benefits of SDN and NFV without compromising carrier grade availability and line rate performance.


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Radisys is an Associate member of the Intel® Intelligent Systems Alliance.

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Simon Stanley

Roving Reporter (Intel® Contractor), Intel® Intelligent Systems Alliance

Principal Consultant, Earlswood Marketing

Follow me on Twitter: @simon_stanley