Tuesday, October 28, 2014

Blueprint: Essential Elements of Transport SDN

by Stu Benington
Vice President, Cloud/SDN Business Unit, Coriant

There is a great opportunity emerging for service providers, driven by the widespread adoption of cloud-based applications by both enterprises and consumers. It’s a chance to capitalize on the elastic network needs of on-demand cloud-based services to create new sources of revenue and tighten control of CAPEX/OPEX costs.

The lack of elasticity in most of today’s static networks makes it difficult for service providers to deliver the on-demand bandwidth needed to support dynamic applications in a fast, cost-effective and profitable way. Also, the on-demand nature of cloud-based applications facilitates unpredictable traffic volumes that are often characterized by spikes in usage and variable traffic patterns. This challenges service providers to plan and engineer appropriate levels of network performance to satisfy users’ application demands.

In today’s fiercely competitive networking market, service providers need a new business model that enables them to capitalize on the proliferation of cloud-based applications and services. To this end, service providers must seek networking solutions built on Software Defined Networking (SDN) architecture.

An SDN-based solution transforms today’s rigid transport infrastructure into a highly programmable network that is as adaptive, efficient and scalable as data-center computing and storage resources. Transport networks become sufficiently flexible to deliver the bandwidth and performance needed for cloud-based applications on demand.

SDN shifts control of the network from internal elements to an external centralized controller and abstracts the underlying hardware infrastructure from the applications. The external controller now decides which network paths packets should take based on application requirements and the users’ willingness to pay. Then, using a standardized interface such as the NETCONF or OpenFlow protocols conveys its instructions to the forwarding plane, which remains within network elements such as routers and switches.

Transform the Network with Dynamic, Multi-Layer Transport

Service providers need to leverage the differentiated value of existing assets, including their network resources, networking expertise, and investments in the network brand. By deploying an SDN solution that combines dynamic multi-layer (L0-L3) transport with dynamic control, service providers can transform their network and service-delivery model while also maximizing return on their embedded investments. Such a solution enables the programmable network to respond to applications, rather than forcing applications to respond to the network. Using the intelligence in the external controller, the network can update dynamically, in real time, to accommodate the needs of a given application. In addition, these capabilities can be complemented by Network Functions Virtualization to move network resources to optimal locations that are then dynamically accessed by SDN.

The Essential Elements of SDN

A successful SDN has three essential attributes:

1. Programmability: Enables the network to adapt to the dynamic requirements of end users and applications, making it possible for service providers to introduce and modify services very quickly.

2. Multi-layer, multi-vendor end-to-end integration: As more applications and services move to the cloud, service providers must be able to integrate computing and storage resources across:

  • multiple vendors’ platforms
  • multiple segments of the network – access, metro and core; fixed mobile and data center
  • multiple optical and packet protocol layers

SDN helps manage this ecosystem of resources, including optical-layer advances such as flexible grid, ROADMs and photonic mesh, to deliver an end-to-end global view of the network.

3. Openness: Packet-optical transport networks comprise multiple vendors’ platforms and technologies. They depend on standards-based protocols for interoperability at both the virtual and physical layer. SDN’s open and collaborative software-based development process focuses on applications and accelerates innovation. By deploying a truly open SDN solution, service providers can introduce new functions and applications written by vendors, third-party developers, and service providers, with ease. It also provides flexibility for evolutionary steps from legacy environments to SDN programmability. An SDN solution that addresses these critical attributes is the foundation of the programmable network necessary to support and empower cloud-based applications.

SDN Use Cases


As SDN-enabled solutions move from laboratory trials to field trials, the hard evidence in support of the SDN business case is growing:
  • Bandwidth on Demand - An end user or an application may request temporary bandwidth between data centers, a lower latency on an existing connection (performance bursting) or an increase in bandwidth for cloud bursting. It can also provide user-defined connectivity for applications in the same “do it yourself” manner as using virtual machines (VMs).

    When the SDN-enabled network receives these requests, it determines the optimal path through the network. An optimal path is one that meets but does not exceed the requested performance criteria. For example, a service provider does not want to allocate a 10 Gb/s link if a 1 Gb/s link suffices. Similarly, a service provider does not want to allocate a 5-millisecond (ms) path to fulfill a request for a 10-ms delay if a 10-ms path is available. The goal is always to use the network’s least-cost resources first, with significant higher granularity than was previously available.

    Allocating network resources on demand benefits both the service provider and the customer. The service provider increases revenues by utilizing the network more efficiently and cost-effectively and more effectively monetizing network assets. The ability to create bandwidth interconnection services also increases network availability in terms of QoS, redundancy levels and protection. The customer gets the elastic bandwidth necessary to match their changing compute and storage needs, and also potential long- term cost savings.
  • Network Slicing - a process by which the service provider virtually apportions segments of the network across multiple products and layers to satisfy the specific requirements of a particular end user. For example, a service provider could use network slicing to partition services for a retail carrier in a wholesale environment or for a large enterprise. By eliminating the need to virtualize every single network element, the SDN-enabled network enables the service provider to deliver precisely what the end user needs – and do so much more easily, faster and cost-effectively than before.
  • Network Defragmentation - existing network connections are optimized by dynamically and continuously packing them in a more efficient manner on the network. Operating across both the optical and packet layers of the network, SDN-enabled network defragmentation packs flows to improve the network utilization. Because of SDN’s ability to provide a multi-layer, end-to-end view of the network, service providers can boost network utilization by 50- to over 90 percent.
  • Application-based Forwarding - SDN allows a service provider to set up the desired flow for an application according to that application’s specific requirements. For example, a service provider needs to upload into the data center all the data associated with an ERP system backup. Given the security and reliability requirements of that ERP system backup, it’s unlikely the service provider would choose the lowest-cost path to route that application through the network. Contrast that application’s requirements with those of a mobile user’s video application. When downloading that application, the user wants a lot of throughput and a low-cost connection, not necessarily a low-latency connection. SDN enables the service provider to take into consideration all the factors concerning a specific application’s requirements and come up with a recipe for the most appropriate and efficient flow through the network. Additionally, this service could be “calendared” at specific time intervals or done intermittently at the discretion of the provider.

SDN - A Framework for Sustainable Success

SDN is driving a network revolution. By transforming the transport network into a more elastic, adaptable and ultra-scalable entity, SDN creates a framework for service providers in which to create new, billable applications and services. That framework also encompasses the tools and techniques needed to create more sustainable business models and strengthen the ability to compete.
SDN is delivering significant financial and competitive benefits by enabling service providers to do the following:
  • respond to changing market conditions by creating new applications and launching new services faster
  • shorten dramatically the time required to dimension and provision the network resources necessary to support specific applications 
  • satisfy end-user requirements for on-demand bandwidth in an efficient and profitable manner 
  • reduce operational complexity through network simplification and automation 
  • reduce CAPEX and OPEX by a) enabling customers to tailor their application-specific connections and b) enabling service providers to distribute loads, with maximum speed and efficiency, among the most appropriate network resources 
  • free themselves from being locked in to specific vendors’ solutions and associated cycles of forced platform upgrades 
  • generate additional revenues that strengthen their margins 
By deploying the right SDN-enabled solution, service providers can capitalize on the opportunity to
migrate their multi-layer transport networks according to their individual business strategies and budgetary considerations. In doing so, they can protect their existing investments in switches/routers, optical transport platforms and network management systems in a programmable network that is essential for long-term success in an application-driven ecosystem.

About the Author

Stuart Benington is Vice President of the Cloud/SDN Business Unit at Coriant where he is responsible for leading the business unit, including strategy and R&D, focused on software defined networking (SDN), network virtualization, and cloud connectivity.

Prior to this role, Mr. Benington worked at Tellabs where he held a variety of strategy, marketing, engineering and product planning positions across several product groups, including Tellabs’ Data Products, Optical Networks, Network Management, and Managed Access Systems.  He started his career at Marconi (Reltec) working in product management for their broadband access solutions.

Mr. Benington has more than 20 years of experience in the telecom industry and holds Bachelor of Science degrees in economics and computer science from Purdue University and a Master of Business Administration degree from Northwestern University’s Kellogg Graduate School of Management.

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