SD-WAN for Beginners

SD-WAN for Beginners

I. Presentation

In this article, I will introduce you to SD-WAN, a very fashionable solution in recent years and increasingly used by companies to interconnect their networks with each other and to optimize the use of bandwidth.

Before reading this article, I recommend that you read this one:

II. What is SD-WAN?

Let’s look at the acronym SD-WAN which means Software-Defined Wide Area Network : What does that mean ? On the one hand we have “Software-Defined“which can be translated as”software defined“and on the other hand, we have”Wide Area Network” which evokes wide area networks WAN. Thus, we can say that SD-WAN is a software-based approach to managing a WAN network or a software-defined WAN, if you prefer.

A. A few words about MPLS

Before going into detail about SD-WAN, I think it is essential to tell you about the MPLS (Multiprotocol Label Switching). For more than 20 years, companies that want to interconnect several sites with each other rely on what is called an MPLS VPN. Thus, this private network which does not pass through the Internet allows a user located on site A to communicate with a server located on site B: essential when you host your servers internally. When a user needs to access the Internet, they leverage their site’s Internet connection. Arguably, MPLS is the traditional way to interconnect sites.

To have an efficient MPLS network, the company must have reliable connections (with an appropriate level of service – SLA), with low latency and a guaranteed throughput corresponding to the needs. Even if this is no longer the case, for a long time it was necessary to have all subscriptions with the same operator to set up MPLS. Thereby, setting up MPLS can be cumbersome and expensivein addition to requiring advanced technical networking skills.

Over time, uses have evolved, and in recent years, companies have been turning to the Cloud, whether for corporate messaging, for hosting files, or even all of the servers, the Cloud model is clearly on the rise. In this case, the MPLS network loses interest, because it is in place, it is expensive, and yet it is not used as much as before, because there is more demand on the public network to access the Internet. Today, SD-WAN responds to this trend and this new way of designing computer networks.

Note: Although more and more companies are turning to SD-WAN, MPLS should not be ruled out.

B. Discovering SD-WAN

SD-WAN is changing the way we interconnect networks, with respect to MPLS technology. It has the advantage of support a variety of transport mediawhether it is a fiber optic connection (FTTH, FTTO, etc.), a 4G or 5G connection, etc… As long as the connection is present, the SD-WAN will be able to position itself on top to set up its interconnection tunnel with another site. The flows passing through an SD-WAN network are secure.

Since it supports a multitude of media, SD-WAN offers more flexibility to businesses, because it is possible to subscribe to less expensive offers according to the needs, with different operators. A good way to make the competition work for optimize costs. Otherwise, interconnection is permitted without geographic location being a constraint like you can with a VPN.

Scheme SD-WAN

This is all the more true as the SD-WAN is able to perform application routing. One can imagine that the link with the highest speed (a very simple FTTH, for example) is associated with flows to the Internet, messaging, etc… While another connection, with a lower but guaranteed speed, will be associated with flows for VoIP. You would have understood it, the same SD-WAN box is able to manage several connections at the same time and to distribute the traffic on the different links according to the uses.

Speaking of SD-WAN box, you should know that this technology is supported by major market players, including Cisco, Fortinet, Stormshield, Sophos, Palo Alto Networks, but also some French players. Popular cloud environments like Azure, AWS and Google Cloud are also SD-WAN compatible.

SD-WAN management, whether for configuration, but also monitoring and flow control, is carried out froma centralized management system which allows to have an overview of all its interconnected sites. To facilitate the provisioning a new site and integrating it into its SD-WAN networkyou should know that some systems support the “ZTP” function, that is, Zero-Touch-Provisioning : the device goes back to the centralized management environment, retrieves its configuration, and voila!

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#SDWAN #Beginners

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