What is difference between SDN and SD-WAN?
Software-defined technology refers to using software to control elements of a system. One of the earlier—and simpler—iterations of software-defined technology is an engine control application for improving a car’s performance. Before people started using software to control things like the turbo boost, fuel efficiency, and traction control, when you bought a car, you just got in and drove, hoping it would serve your needs.
What is SDN
Software-defined networking (SDN) and software-defined wide-area networking (SD-WAN) give users the ability to “tune” or manipulate how the network behaves, creating virtually unlimited possibilities for enhanced performance and customization.
Software-defined networking is an approach to network architecture that allows users to control the network using software intelligently. Operators can centrally manage the network and customize its performance to suit the organization’s unique needs. Users employ application programming interfaces (APIs) to program the network instead of relying on controls physically located on individual pieces of hardware.
Typical Features of SDN
- SDN presents several opportunities that would be otherwise unattainable
- Programmable network behaviour: Everything from when and how a network is used to provisioning resources and bandwidth can be controlled using programming.
- Convenient, centralized control: Network engineers can manage several network elements without leaving their desks. There is no need to travel to hardware-based interfaces again and again to tweak network equipment performance.
- Virtualization: Not only does virtualization make it possible to configure and control different network elements, but it also opens the way for creative possibilities. Given the option to control various network devices and their parameters, engineers can easily conceive innovative solutions and quickly troubleshoot multiple issues.
SD-WAN & SDN: similar in many ways, starting with the “SD”
SD-WAN and SDN have a common heritage, beginning with separating the Control Plane and the Data Plane. Both are designed to run on commodity x86 hardware, both can be virtual, and both support the integration of additional Virtual Network Functions (VNFs) such as security or WAN acceleration.
SDN was built to support the modern computing needs found in Local Area Networks (LANs) and Service Provider networks (for example, by our company to deliver wavelength services). The goal was to develop dynamic, flexible, scalable connectivity to support changing demands in the DC (data centre) and on core networks. SDNs are directly programmable, providing an agile centrally managed platform that decouples the Control Plane – decisions about where traffic is routed – from the Data Plane – which determines how traffic is forwarded.
These same underlying principles also power SD-WAN technology. That said, SD-WAN and SDN are not the same things.
SD-WAN vs SDN: Understanding the differences
- Like many relatives, SDN and SD-WAN look a bit alike, but you often find that, whereas the pear never falls too far from the tree, some pears may develop a different taste/colour. The SD-WAN network provides software-defined application routing to the WAN or Wide Area Network. It connects an organization’s geographically distributed locations (headquarters, data centres, branch offices, remote and mobile users) nationally or globally. While on the other hand, SDN is primarily focused internally, within the LAN (locally) or the Service Provider’s core network.
- SDN is completely programmable by the customer or user and allows for efficient change and configuration management. While SD-WAN as a service is built on SDN technology, the programming is handled behind the scenes by the SD-WAN vendor, eliminating the complexity for the end user.
- SDN is focused on the internal network, be it the LAN or the core service provider network. At the same time, SD-WAN is focused on enabling connections between networks and users over the WAN.
- SDN is enabled by NFV, Network Function Virtualization, providing multiple virtualized network functions via software that until now were previously built into proprietary, closed systems. In contrast, SD-WAN provides software-defined application routing that can be virtualized and run either virtually or on an SD-WAN appliance.
- SD-WAN takes you from packets to apps and beyond. The technology behind SD-WAN changes the paradigm from a packet-based network routing system to an application-based routing system. This enables organizations to use consumer-grade broadband Internet with improved quality and performance and, importantly, a lower cost per megabyte than previously available with MPLS.
- SD-WAN technology also provides agility and flexibility while maintaining centralized, pre-defined business policies controlling how applications get routed. The resulting visibility and control allow you to identify applications running across the WAN and set policies on their prioritization and use.
- SD-WAN also uses dynamic WAN selection to route those apps over the best-performing pathways. In addition, SD-WAN router lets you use multiple available links in an “active/active” configuration to provide load balancing and failover with little-to-no perceived interruption. Traffic between sites flows over dynamic, fully encrypted tunnels and can be segmented, providing a high level of security.
All “SD” driven technologies are not created equal. While it may have previously seemed confusing, as noted above, SD-WAN removes the complexity from the end user, providing an easy-to-use set of tools and analytics for network management.
Of course, while this may make it sound easy, leading some organizations to decide to implement SD-WAN devices on their own, there are benefits to leveraging an experienced service provider to help you get the most out of your implementation. Especially if you want to integrate SD-WAN into an existing private or hybrid network, you’ll need a strong knowledge of how associated services (voice, video, WiFi, etc.) are configured and how they collectively may impact your security model. These are the things a knowledgeable provider can help you with, among others.