A Practical Path to

Network Modernization

Progressive enterprises are combining elements of traditional and software-defined networks to reap the rewards of automation without the pain of rip-and-replace overhauls.

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oftware-defined networking (SDN) has long promised valuable benefits compared to traditional networking technology. Yet SDN still struggles to capture the hearts and minds of many network administrators. That’s puzzling to some since it appears to be a natural extension of server virtualization strategies. In the networking world, this means enabling enterprises to centrally manage traffic and hardware configurations without the controller being tied to specific network devices. This approach promises other benefits as well. One of the biggest benefits is that network administrators can reconfigure and update scores of devices from a single location rather than having to manually adjust each unit separately. Central control also lets managers simultaneously apply quality-of-service (QoS) and security policies across the network and be assured none of the devices are overlooked. The opportunity to reduce manual intervention and alleviate management complexity comes at a pivotal time. Campus network managers are under intense pressure to support a host of performance-sensitive applications, such as VoIP, streaming video,

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and virtual desktops. Each of these applications requires reliable QoS levels and the ability to deliver low-latency performance. In addition, modern networks must provide high reliability and availability as organizations build core business processes around these demanding applications. Against this backdrop, SDN looks like an innovation whose time has come. So what’s not to like? Widespread SDN adoption is coming face to face with some practical realities that raise challenges for IT. One of the biggest of those realities is the impracticality of ripping Sponsored by

A Practical Path to Network Modernization out traditional network infrastructures and replacing them with SDN devices and software. A lack of trained professionals is also holding back SDN deployments — many enterprise network technicians don’t have hands-on experience implementing and supporting SDN. These specialists are already straining to support existing network infrastructures and have little time to develop SDN expertise or oversee large-scale rollouts of a sophisticated new technology. By contrast, traditional networking technology is mature and already well-understood by network professionals. Fortunately, IT managers don’t have to choose between making an aggressive all-in commitment to SDN or denying their

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organizations a modern campus network. Hybrid software-defined networks offer a practical path forward where enterprises can begin to take advantage of higher levels of network automation associated with SDN by gradually rolling it out across the campus. The result: Organizations can capitalize on existing network investments while readying their networks for the future. The key to this evolution is a flexible network architecture and core switches designed to excel in both traditional and SDN environments.

In Detail: Hybrid Networks The SDN concept focuses on a network architecture designed around a central controller that gives administrators a single view of all network resources, as well as the power to manage all the routers, switches, and traffic flows reaching back to the network core. The impact is potentially significant. First, by being able to use a single, logical switch, network administrators are relieved of having to schedule time and personnel to manage separate access and core networks. In addition, a logical SDN switch reduces the risk of access node configuration errors and the need for complex protocols, such

as Spanning Tree, to avoid traffic loops and unnecessary replication of data. These are some of the most widely touted potential benefits of SDN. But as industry experts have noted, network planners aren’t rushing to make a wholesale leap to SDN.

Hybrid SDNs let enterprises take advantage of higher levels of network automation. Unfortunately, sticking with the status quo means enterprises must live with some nagging shortcomings: Traditional network designs create separate layers for access switches and for core/aggregation switches. In addition, they need manual configurations. Traditional networks also require numerous core/aggregation switches, an added complexity that is unnecessary with today’s architectural innovations. What’s more, if enterprises use equipment from multiple vendors within different tiers in their traditional campus networks, they must manage and maintain various operating systems and commandline interfaces (CLIs). This approach adds yet another layer of complexity.

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A Practical Path to Network Modernization Weighing the pros and cons for both SDN and traditional networks, some IT managers are seeking an alternative option that balances the best of these two networking worlds.

With hybrid SDN, IT staff no longer has to make manual changes to network switches and can focus on more strategic initiatives. Hybrid SDN creates a way for enterprises to modernize their infrastructures in a cost-effective, iterative manner without the disruption of rip and replace. At the same time, the hybrid approach offers the value of new technology, replacing multiple network tiers with one logical

tier. A centralized network controller acts as the core/aggregation switch, with a single operating system and CLI from access to core. The hybrid approach is flexible enough for administrators to use the central controller to manage either traditional access switches or associated network nodes designed for SDN implementations. When paired with traditional nodes, the SDN-capable switch operates as a conventional switch rather than as a central controller. But when newer devices comprise all or a portion of the access nodes, the sophisticated switch can centrally manage important tasks, such as setting QoS parameters, changing device configurations, and updating security

policies. In addition, enterprises can support predominant campus traffic patterns with no local switching and no Spanning Tree required. This means IT managers can assign technicians to initiatives that are more strategic than the task of manually making changes to every switch in the network.

Modern Switches for Hybrid Networks Hybrid infrastructures require a network core composed of switches designed for scalable and flexible SDN architectures. For example, IT managers can deploy the Dell C9010 network director switch as an access or aggregation/core switch to support up to 240 10-Gigabit Ethernet (GbE) or

3 Practical Steps to a Modern Network C9010

Existing 1/10 GbE Switches

C9010

C9010

Existing 1/10 GbE Switches

C1048P or N-Series

C1048P or N-Series

C1048P or N-Series

With the right core/aggregation switch, network administrators have a practical way to transition from multitier architectures to flexible software-defined implementations. From left to right, the Dell C9010 network director switch supports a traditional, a hybrid, and a fully software-defined network.

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A Practical Path to Network Modernization 60 40-GbE Ethernet ports. This includes a combination of port speeds and media types, such as copper, fiber, and direct attached cable. The switch is scalable up to 4,000 virtual or host ports, which can be managed centrally. In addition, the

Having multiple networking technology vendors lets enterprises avoid vendor lock-in and creates a competitive purchasing environment. switch is engineered for the possibility of supporting higher data rates in the future, so enterprises may standardize on 10 and 40 GbE today and eventually upgrade to 100 GbE in the future to meet the growing bandwidth requirements. When the C9010 is supporting traditional Layer 2 and Layer 3 switches, the forwarding plane is local to these switches, so organizations can manage networks as they would with any traditional architectures. The C9010 chassis can function like any other core chassis with any Ethernet device connected to it. The C9010 is particularly effective when it’s paired with Dell C1048P rapid access nodes. These nodes extend the network director functionality to the edge of the network. That means administrators don’t

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directly configure the rapid access nodes. Once the rapid access notes are connected to the director switch, it handles all of the management and troubleshooting duties. Thus, in a hybrid configuration, enterprises can centrally manage a campus network using the C9010 in conjunction with existing switches and the C1048P rapid access nodes or Dell N-Series switches. Over time, as traditional switches reach the end of their useful lives, IT managers can replace them with C1048Ps or Dell N-Series switches to make a deeper commitment to SDN. Interoperability is another important characteristic. Dell Networking has always supported multivendor environments, and accordingly the Dell C-Series switches can support 1-, 10-, and 40-GbE devices from most other vendors. Enterprises that have

deployed N-Series switches can upgrade them to a version of software that converts them to rapid access nodes to take advantage of the network director/rapid access node architecture. Industry experts advise having more than one supplier of networking technology to avoid vendor lock-in and to create a competitive environment when negotiating purchases and contracts. Having multiple vendors also enables enterprises to choose the best mix of technologies for each requirement.

First Steps to Hybrid Campus Networks Hybrid SDN implementations provide a natural stepping stone from traditional infrastructures to modern communications

Benefits of Hybrid SDN Enterprises can capitalize on a range of benefits by implementing core switches that are able to support software-defined networking capabilities. Among those benefits are: • Reduced management complexity • Centralized management that reduces risk of access-node configuration errors • Support for existing investments and future upgrades • The ability to roll out new policies and software updates without having to manually change every affected device on the network

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A Practical Path to Network Modernization platforms. They also complement other IT areas transitioning to a software-defined approach, including servers and storage resources. What’s the best way for network administrators to make this move? Networking veterans say four key steps can move enterprises in the right direction. Step 1 Define business needs. As with any new technology, the goal of SDN isn’t to implement the latest and greatest innovation, but rather it is to serve business interests. IT and networking administrators should meet with lineof-business managers to understand new initiatives and determine how a more flexible and scalable campus can further those goals. Similarly, close communications with operations staff may uncover opportunities for business process efficiencies made possible by network modernization.

Step 3

Evaluate technology options with an eye to the future. Beware of vendors that lack a true commitment to open standards because this may inhibit enterprises from fulfilling the potential of SDN. In addition: • Watch out for vendors that don’t offer the highest levels of performance in their core/aggregation switches and nodes. • Look for equipment that provides a foundation for future enhancements to support the enterprise as it transitions from hybrid to fully software-defined networks. • Finally, make sure the technology lets you adopt higher-speed Ethernet standards without swapping out core switches. Step 4

Step 2

Avoid large-scale, disruptive moves.

Estimate the cost reductions resulting from having to invest in fewer core/aggregation switches, a saving made possible when moving to centrally managed, singletier architectures. Similarly, hybrid SDN

• Capitalize on hybrid SDN to support gradual migrations that squeeze the most value from existing hardware investments and give staff time to hone technical skills. • Identify a use case that is appropriate for a small pilot project to test SDN, and then

Make the business case for investments in hybrid SDN.

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implementations free IT technicians from many routine management tasks, allowing managers to reallocate these resources in more productive ways.

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About Dell Dell listens to customers and delivers the innovative technology solutions they trust and value. Committed to finding better ways for our customers to be more efficient, more mobile, more informed, and more secure, Dell is one of the world’s leading providers of technology solutions to people and organizations of all sizes. The company serves 98% of the global Fortune 500, 10 million small businesses, students and teachers in 400,000 classrooms, every G20 government, and more than 200,000 physicians.

build on that experience to roll out the technology in other areas.

A Foundation for the Future Network administrators don’t have to endure the disruption of rip-and-replace network upgrades to realize the value of SDN. Hybrid SDN implementations provide an economically viable path forward. They let enterprises modernize at their own pace, while quickly reaping the benefits of centrally controlled, single-tier networks that can support current and future business needs. To learn more, contact your Dell representative or go to Dell C9000 Series Switches.

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