SDN Orchestration Explained A Deep Dive into a Crucial Component of Software-Defined Cloud Exchange Networks
Table of Contents Introduction. 3 Back Story: Defining Terms. 3 Cloud Exchange Network. 3 Orchestration in Network Function Virtualization. 3 Orchestration in Software-Defined Networking. 3 Applying Orchestration in the WAN. 3 Requirements for Effective WAN Orchestration. 4 Network Operating System. 4 Application Interfaces. 4 Putting it All Together. 4 Benefits of Orchestration. 5 Service Provider Benefits. 5 Enterprise Benefits. 6 For Best Results, Choose Carefully. 6 About Sonus. 7 2
Introduction In software-defined networks, the concept of orchestration is central to ensuring proper function. Orchestration is well-understood with respect to SDNs that exist in a data center, but when the concept extends to networks that connect data centers to each other and cloud service providers to customers often referred to as cloud exchange networks the orchestration function has to take on different functions that are only now becoming well-defined. In a cloud exchange network, orchestration addresses two challenges: enabling access to applications that may be in one or more data centers, and connecting to the cloud exchange network with the appropriate level of service, as defined by business policies. When it can effectively address these challenges, orchestration provides a number of benefits, including: Operational cost savings, by making it easy to dynamically provision cloud exchange network services Faster service turn-up, using self-service portals Higher network resource utilization rates and lower capital costs In this paper, we ll take a deeper dive into how orchestration delivers on these benefits in a cloud exchange network for both solution providers and their customers, how orchestration is applied, and the key attributes of an effective solution. Back Story: Defining Terms Before diving in, it s helpful to define some terms, because orchestration can mean different things depending on where it s applied. Cloud Exchange Network A cloud exchange network provides connectivity between clouds, whether of the public, private, or hybrid variety. More and more, applications and data are migrating away from customer premises and into cloud environments. In many instances, a single customer may be using services from several cloud providers. A cloud exchange network connects the customer s data center to each cloud service provider, and connects the providers and customer data centers to each other. From the customer perspective, the cloud exchange network is a seamless infrastructure connecting users to all of their mission-critical data and applications. Orchestration in Network Function Virtualization To understand how orchestration plays into the cloud exchange network equation, we first need to establish that it s related to but different from orchestration as it applies to network function virtualization (NFV). NFV orchestration is used to coordinate the application resources needed to provide a service, using a variety of virtualization software and industry-standard hardware. Cloud service providers or global telecom operators use NFV orchestration to quickly deploy services and virtual network functions (VNFs), using cloud software rather than specialized hardware networks. Orchestration in Software-Defined Networking Software-defined networking (SDN) orchestration, on the other hand, is the ability to program automated behaviors in a network. SDN orchestration coordinates all the networking hardware and software elements required to support applications and services. For example, SDN orchestration may be used to kick off the series of automated processes required to fulfill a customer service order generated either manually or via a customer web site. This is the type of orchestration we ll be focusing on in this paper. Applying Orchestration in the WAN As applied to cloud exchange networks, orchestration is the translation of business policies regarding service levels assigned to each application into appropriate network paths. In essence, it means adapting the network to the needs of the application. That requires an effective network interface or API to enable applications to speak to the network, to request a connection. Then the network must be able to establish a path that has the appropriate level of service for that application. If it s a real-time application such as voice or video, that means providing a connection with low latency and sufficient bandwidth. Depending on what 3
else is happening in the network at that particular time, providing such a connection may require moving lower priority traffic to different network paths. It s the orchestration function that initiates the actions that result in all traffic being assigned to appropriate paths all in real time. Requirements for Effective WAN Orchestration Doing this effectively requires a high level of communication among many network components and systems, all working in concert. In this section, we ll take a look at the required components and systems. Network Operating System A network operating system which either contains or communicates with an SDN controller acts as the control plane for the network. It contains the topology (a map) of the entire network that is under its control, and it knows about each connection in the network and its characteristics, such as available bandwidth and expected latency. Ideally, the network OS performs this topology management through self-discovery of the network topology and the configuration parameters of each connection; there shouldn t be a need to program all this information manually. The network OS needs real-time knowledge of network resources, understanding the state of the devices in the topology and tracking all flows across the network. Armed with this data, the network OS can perform path computations, giving it the ability to determine the best path for each application request. At the same time, it needs to be able to keep up with any network changes as bandwidth and switches are added or removed, whether intentionally or due to a failure of a given link. The network OS is also responsible for policy assurance, to make sure actual network traffic behavior matches the expected behavior for any given traffic mix. By metering traffic flows, limiting the lower-priority traffic such that high-priority applications get the level of network service they require, the network OS ensures SLAs for applications are met. Given its critical function, the network OS must run on high-availability servers, typically virtual servers configured in a cluster for redundancy. Application Interfaces Application interfaces provide the avenue through which applications request network services from the network OS. While any number of APIs could be used for this function, the most widely used adhere to the REST architecture, for REpresentational State Transfer also known as RESTful APIs. RESTful APIs are flexible and lightweight in nature, requiring little bandwidth. They are often used for Web services applications, and lend themselves well to the cloud exchange network orchestration function. Applications could request services in at least a couple of ways. One is via a customer portal, where customers can specify how much bandwidth they want for a particular application. Or an application such as Skype for Business may support an API on its own, enabling it to communicate with the network OS each time a user wants to fire up a videoconference, for example. The API should also provide for a feedback mechanism, to allow for performance measurements and management information, including alerts for when a given connection is nearing a predefined threshold in terms of utilization. Putting it All Together With all of these components working together, here s how the orchestration function works in practice. The network OS receives a service request for a certain amount of bandwidth from point A to point B for a specific time frame, perhaps for an audio conference. That service will have a relatively high priority level and attributes which include low latency. The control plane determines the best possible path for that request. Its path choice is then orchestrated, or configured, in the appropriate network elements, including switches and inter-switch links. 4
The audio conference launches, everyone is connected, and all is well. But networks are never static. Maybe another user requests a video conference, and then another, followed by another audio conference call. Or maybe a switch port fails. Now the policy assurance function comes into play. Based on feedback from the data plane to the control plane, the policy function determines whether new data flows are needed and what characteristics they should have. Maybe some lower-priority traffic needs to be bumped off some low-latency links and onto a lesser connection to make way for all those audio and video connections. Whatever the case may be, the orchestration function makes it happen. Benefits of Orchestration The orchestration function is really what makes cloud exchange networking services so effective, producing a number of benefits for both enterprises and service providers. Service Provider Benefits Orchestration allows service providers to effectively and dynamically allocate network resources for their cloud exchange network service offerings. Service providers can enable customers to drive the process from an easy-to-use Web-based portal, meaning customers can turn up services quickly with minimal on-boarding required on the part of service providers. With no manual provisioning required, service providers save significant operating expense. At the same time, they can be more responsive to customer needs, able to perform in minutes tasks that previously took hours or days. That, of course, will increase customer satisfaction. That is exactly the experience that Telstra had after implementing SDN technology from Sonus to build a cloud exchange network. Telstra is one of the world s largest specialist network and data center providers, with high-capacity submarine cable infrastructure stretching from India to the United States and 24 data centers in Asia and Australia. Telstra s PEN Platform allows customers to dynamically customize and configure networks based on performance and QoS requirements under a flexible pricing model. IT managers, for example, now have the capability and flexibility to create a virtual data center spanning Asia and the Pacific. They can route data flows on demand across links based on business metrics, such as latency and bandwidth requirements. The solution, based on the Sonus VellOS network operating system, gives enterprise network administrators the ability to allocate within minutes how much bandwidth a particular application should be provisioned with through the network. What s more, they can do so from their own dashboard, with no help from Telstra a benefit for both the customer and Telstra alike. Customers can create a virtual environment that provides access to major carriers and data centers, private clouds and external cloud vendors. Figure 1 below represents a simplified view of dynamic data center interconnection, starting with an enterprise customer specifying its requirements through allocation of network resources and feedback metrics on network behavior and usage. Figure 1. Dynamic Data Center Interconnect 5
Enterprise Benefits Enterprises likewise save on operating costs due to the ease of configuring new services. What s more, the services are far more flexible compared to the relatively static nature of traditional WAN services. Enterprises will also find they save money because they can operate at far higher utilization rates compared to traditional WAN architectures. No longer do they have to configure the WAN for the worst case scenario. With software-defined cloud exchange networks, they can operate at high utilization rates, knowing that network resources will be allocated dynamically as needed, based on orchestration of business policy decisions. State Street Bank, for example, had 22 Gigabit Ethernet, MPLS-based WAN links connecting eight branch locations running at just 20% utilization. It replaced them with just seven carrier Ethernet connections using Sonus VellOS solution. Those seven links now operate at up to 90% utilization, and WAN costs have dropped from $198,000 per month to just $42,000 per month. Over 36 months, costs dropped from more than $7 million to about $1.5 million, for a savings of more than $5.5 million. As the State Street example shows, software-defined cloud exchange networks enable enterprises to use less-expensive WAN services without sacrificing availability or performance. That s because the quality of service functions that customers pay for with more expensive carrier services such as MPLS can be delivered in the cloud exchange network by aligning business policy decisions with network resource allocation, initiated via an orchestration function. The savings can quickly be enough to pay for the solution, as State Street learned. For Best Results, Choose Carefully With such savings to be had, it s clear that cloud exchange network services will play a significant role in network architectures of the future. It s also clear that the orchestration function is key to making the services work effectively, so customers need to ensure that the solution they choose meets all the requirements. Sonus VellOS network operating system includes all the crucial features and functions for effective orchestration in a cloud exchange network, including automated network topology discovery and REST API-based configuration and provisioning tools. VellOS is application-aware, making it possible to orchestrate and dynamically deliver just-in-time cloud connectivity, optimize cloud exchange network utilization, and improve application performance. For service providers that do not want to build their own portal, Sonus also supplies its VellOS Customer Application Portal, a customizable, multi-tenant, Web-based portal that allows providers to enable self on-boarding for customers, as well as service selection and bandwidth on-demand. Customers manage their own offerings, handling changes in bandwidth, latency, and the like with drag-and-drop simplicity. What used to take weeks and months to negotiate and provision can now be done in minutes by the customer, with no service provider interaction. Customers can even see how much different configurations will cost, using the portal s integrated pricing/billing calculator. VellOS also includes its FarSight visualization tool for network and application performance, providing a collection of networkcentric dashboards that correlate network activity with application performance, enabling administrators to fine-tune networking resources in real time for optimal applications and services performance. To learn more about how Sonus VellOS delivers a superior cloud exchange networking experience, click here. 6
About Sonus enables and secures real-time communications so the world s leading service providers and enterprises can embrace the next generation of SIP and 4G/LTE solutions including VoIP, video, instant messaging, and online collaboration. With customers in more than 50 countries and nearly two decades of experience, Sonus offers a complete portfolio of hardware-based and virtualized Session Border Controllers (SBCs), Diameter Signaling Controllers (DSCs), Cloud Exchange Networking Platform, policy/routing servers, and media and signaling gateways. For more information, visit www.sonus.net or call 1-855-GO-SONUS. Sonus is a registered trademark of Sonus Networks, Inc. All other company and product names may be trademarks of the respective companies with which they are associated. North American Headquarters APAC Headquarters EMEA Headquarters CALA Headquarters 4 Technology Park Drive Westford, MA 01886 U.S.A. Tel: +1-855-GO-SONUS 1 Fullerton Road #02-01 One Fullerton Singapore 049213 Singapore Tel: +65-68325589 Edison House Edison Road Dorcan, Swindon Wiltshire SN3 5JX Tel: +44-14-0378-8114 Homero No. 1933-902 Col. Los Morales, C.P. 11510 Mexico City, Mexico Distrito Federal Mexico Tel: +52-55-1950-3036 Int l Tel: +1-978-614-8741 To learn more, call Sonus at 855-GO-SONUS or visit us online at www.sonus.net The content in this document is for informational purposes only and is subject to change by without notice. While reasonable efforts have been made in the preparation of this publication to assure its accuracy, assumes no liability resulting from technical or editorial errors or omissions, or for any damages resulting from the use of this information. Unless specifically included in a written agreement with, has no obligation to develop or deliver any future release or upgrade, or any feature, enhancement or function. Copyright 2015, Inc. All rights reserved. Sonus is a registered trademark of, Inc. All other trademarks, service marks, registered trademarks or registered service marks may be the property of their respective owners. DS-1501 11/10 7