SD-WAN
08 Dec 2019

SD-WAN or CDN – Do You Need Both?

A CDN or SD-WAN both deliver functionality that improves the performance of web-based applications and services. As the digital age continues to transform the way we transact, communicate, and consume information, online apps and solutions are vital utilities needed to navigate the information economy. However, seamless access to these platforms is not enough. Service providers need to ensure their solutions are resilient and deliver the performance expected by today’s modern technology user.

The Anatomy of an SD-WAN

According to Gartner, a Software-Defined Wide Area Network (SD-WAN) has four characteristics:

  1. It must support multiple connection types (MPLS, LTE, etc.)
  2. It must be able to perform automated dynamic path selection
  3. It must provide a simple, centralized interface for managing the WAN
  4. It must support Virtual Private Networks (VPNs)

Essentially, an SD-WAN is a virtualization solution that operates at the network level of an enterprise infrastructure architecture. By centralizing the control function of a network, it enables organizations to direct traffic securely and intelligently across a Wide Area Network (WAN). This virtual WAN architecture also allows enterprises to leverage any combination of network transport services, including Multiprotocol Label Switching (MPLS), Wireless Broadband Long-Term Evolution (LTE), and other broadband internet services. Ultimately, SD-WAN allows organizations to connect users to their enterprise applications securely.

The distinct advantage an SD-WAN has over a traditional router-centric networking model is that it leverages software and a centralized control function to steer and direct traffic across a WAN intelligently. It achieves this objective through the deployment of two key features, Centralized Orchestration, and Zero-Touch Provisioning.

Centralized Orchestration

As an SD-WAN has a centralized architecture model, it allows network engineers to configure the relevant policies for application performance and security. Not only does this functionality reduce WAN operational expenses significantly, but it also delivers the highest level of application performance that translates into an enhanced end-user quality of experience. The centralized model of an SD-WAN continuously monitors application and the deployed WAN transport resources. This ability gives the platform the power to adapt to rapidly changing network conditions ensuring performance and availability.

Zero-Touch Provisioning

The Zero-Touch Provisioning capability of an SD-WAN allows network administrators to create configurations and policies once and then push them to all networking devices across their WAN estate. This SD-WAN feature negates the need for engineers to configure multiple networking devices at various locations using the standard Command Line Interface (CLI). This capability not only allows for the rapid deployment of network devices, but it also reduces costs and increases efficiencies by ensuring the most efficient utilization of specialized IT resources. It also reduces the risk of human error that translates into consistency and standardization of networking configurations and policies across the enterprise.

CDN or SD-WAN – What is the Difference?

A Content Delivery Network (CDN) like an SD-WAN is a solution that helps organizations improve the performance of web-based applications and, consequently, the experience of end-users accessing those services. However, there is a distinct difference in the mechanisms a CDN leverages to achieve an enterprise’s performance objectives. In addition to the technical variations, the targeted end-user is another distinction that separates the two solutions. SD-WANs ensure optimum performance for users accessing internal applications hosted on the organization’s Wide Area Network. CDN’s, on the other hand, typically improve the performance of external-facing sites and services accessed by an organization’s customers, suppliers, and partners.

How a CDN Improves Performance

A CDN improves the performance of web-based applications by enhancing the responsiveness and page load speeds of websites, online services, and Application Programming Interfaces (APIs). It achieves this objective by narrowing the distance between the end user’s device and the content they need to access. By caching static content as close to the user’s location as possible, when a user initiates a web-based request, a CDN delivers the required data from its closest node.

In addition to improving page load times for static content, CDNs also offer performance improvements for a wide range of other Internet-based content services. Enterprises can leverage a CDN to improve software delivery and boost the load times of their online ads. As content has transformed over the years from static text and images to live video and audio, CDNs have enhanced their offerings to meet the demands of the modern Internet. Live streaming CDN services, whether they be push or pull, support protocols and formats that include HLS, RTMP, MPEG-TS, and HDS.

In addition to providing these content delivery services, CDNs also give organizations the ability to secure access to their content. By providing security solutions such as country access policies, hotlink protection, and token authentication, they can limit access to data stored on their platform to legitimate users and services. In addition to these access control features, CDNs also offer automated failover. Should any node cease rendering services for whatever reason, the globally distributed network of a CDN reroutes traffic automatically, ensuring content remains available to end-users.

CDN or SD-WAN – Both Needed in a Cloud-First World

As the digital age continues to transform the way we work, live, and communicate with each other, the availability and performance of online services are vital. The ability to send, receive, and consume data is a critical utility many businesses and individuals rely on to participate and compete in the modern economy. SD-WANs and CDNs form a vital part of this infrastructure. While both provide the security, performance, and availability needed, the roles they play in the larger networking platform differ.

SD-WANs use centralized software to virtualize the control layer of a network, giving them the capability to leverage any combination of Internet connectivity, orchestrate network operations, and increase efficiencies with zero-touch provisioning. CDNs, on the other hand, deploy a globally distributed content caching service, increasing the page load speeds of websites and providing end-users with uninterrupted video and audio streaming services.

In addition to their technical differences, both technologies serve different end-user groups. SD-WANs increase the performance and availability of internal services that end-users access via the corporate Wide Area Network. CDNs perform a similar function but these are targeted towards public-facing sites and services customers access via the Internet. For organizations utilizing cloud-services, both platforms provide the performance, security, and reliability needed in today’s cloud-first, mobile world.

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