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Introduction to Cisco Software-Defined Wide Area Networking (SD-WAN)

  • Sample Chapter is provided courtesy of Cisco Press.
  • Date: Oct 1, 2020.

This chapter covers the following topics:

  • Networks of Today: This section covers the technologies and challenges of today’s networks.

  • Common Business and IT Trends: This section of the chapter covers the most common trends having a considerable impact on the WAN.

  • Common Desired Benefits: This section examines the benefits and desired outcomes of what businesses are looking for.

  • High-Level Design Considerations: This section covers various aspects of WAN design and things that impact the deployment and operations of WANs today.

  • Introduction to Cisco Software-Defined WAN (SD-WAN): This section examines, from a high level, the benefits and drivers of Cisco SD-WAN.

  • Use Cases Demanding Changes in the WAN: This section covers a variety of use cases businesses are adopting that are putting pressure on the WAN environment.

  • Building an ROI to Identify Cost Savings: This section examines the potential cost savings of deploying Cisco SD-WAN and the value of a well-prepared return on investment (ROI).

  • Introduction to Multidomain: This section examines the purpose of Multidomain and the value associated with having a Mult,idomain environment.

Networks of Today

The IT industry is constantly changing and evolving. As time goes on, there is an ever-increasing amount of technologies putting a strain on the network. New paradigms are formed as others are being shifted away from. New advances are being developed and adopted within the networking realm. These advances are being created to provide faster innovation and the ability to adopt relevant technologies in a simplified way. This requires the need for more intelligence and the capability to leverage the data from connected and distributed environments such as the campus, branch, data center, and wide area network (WAN). Doing so allows for the use of data in interesting and more powerful ways than ever seen in the past. Some of the advances driving these outcomes are the following:

  • Artificial intelligence (AI)

  • Machine learning (ML)

  • Cloud services

  • Virtualization

  • Internet of Things (IoT)

The influx of these technologies is putting strain on the IT operations staff. This strain comes in the form of more robust planning, agreed-upon relevant use cases, and having detailed adoption journey materials for easy consumption. All these requirements are becoming critical to success. Another area of importance is the deployment and day-to-day operations of these technologies as well as how they fit within the network environment. Disruption to typical operations is more imminent with regards to some of these technologies and how they will be consumed by the business. Other advances in technology are being adopted to reduce cost of operations as well as reduce complexity. It can be said that every network, to some degree, has inherent complexity. However, having tools that can help manage this burden is becoming a necessity these days.

Automation is something that many in the industry are striving for. This is because the networks of today are becoming more and more complicated. Oftentimes businesses are operating with a lean IT staff, a flat or reduced budget, and are struggling to find ways to increase the output of what the network can do for the business. Another driver for the adoption of these technologies is improving the overall user experience within the environment. This includes users being able to have the flexibility and capability to access any business-critical application from anywhere in the network and have an exceptional experience. In addition to improving user experience, IT operations is searching for ways to simplify the operations of the network.

There are many inherent risks associated with manually configuring networks. There is risk in the form of not being able to move fast enough when deploying new applications or services to the network. Risk could also be seen as misconfigurations that could cause an outage or suboptimal network performance, resulting in impacted business operations and potentially causing financial repercussions. Finally, there is risk that the business itself, relying on the network for some business-critical services, might not be available due to the IT operations staff not being able to keep up with the scalability demand. According to a Cisco Technical Assistance Center (TAC) survey taken in 2016, 95% of Cisco customers are performing configuration and deployment tasks manually in their networks. The survey also stated that 70% of TAC cases created are related to misconfigurations. This means that typos or incorrectly used commands are the culprit for a majority of issues seen in the network environment. This is where automation shines: being able to have the capability to signify the intent of the change that needs to be made, such as deploying quality of service (QoS) across the network, and then having the network configure it properly and automatically. Consistently and correctly configuring services or features with great speed is a tremendous value to the business. Simplifying operations and reducing human error ultimately reduces risk.

A simple analogy for this would be to think of an automobile. As consumers of automobiles, most people use them to meet a specific desired outcome (in this case, it would be to get from point A to point B). An automobile is operated as a holistic system, not a collection of parts that make up that system. For example, there is a dashboard that provides the user all the necessary information of how the vehicle is operating and the current state of the vehicle. When the user wants to use the vehicle, there are certain operational steps required to do so. Drivers simply signify the intent to drive the car by putting it in gear and using the system to get from point A to point B. Figure 1-1 illustrates this analogy.

FIGURE 1.1

FIGURE 1.1 Automobile as a System

Why can’t networks be thought of in the same way? Thinking of a network as a collection of devices such as routers, switches, and wireless components is how the industry has been doing it for over 30 years. The shift in mindset to look at the network as a holistic system is a more recent concept that stems from the advent of network controllers. The splitting of role and functionality from one another can be described as separating the control plane from the data plane. Having a controller that sits on top of a collection of network devices gives the advantage of taking a step back and operating the network as a whole from a centralized management point—similar to operating an automobile from the driver’s seat versus trying to manage the automobile via individual pieces and components. To put this in more familiar terms, think of the command line interface (CLI). The CLI was not designed to make massive scale configuration changes to multiple devices at the same time. Traditional methods of managing and maintaining the network aren’t sufficient to keep up with the pace and demands of the networks of today. The IT operations staff needs to be able to move faster and simplify all the operations and configurations that have traditionally gone into networking. Cisco Software-Defined Networking (SDN) and controller capabilities are becoming areas of focus in the industry, and they are evolving to a point where they can address the challenges faced by IT operations teams. Controllers offer the ability to manage the network as a system, which means that policy management can be automated and abstracted. This provides the capability of supporting dynamic, scalable, and consistent policy changes throughout the network.

2. Common Business and IT Trends | Next Section

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