First of all, SD-WAN is a technology that leverages the strategies defined in Software Defined Networking (SDN). In this short video titled: What is a Software Defined Network? the narrator @ 4:45 says “why aren’t companies rushing to deploy SDNs? The answer: when applications request it.
“SDN is an architecture, where as SD-WAN is a technology you can buy,”
Andrew Lerner – Research VP, Gartner
The problem is that software developers don’t request high priority for their application and if they did, hardware would ignore it because then all applications would request high priority. Imagine facebook, linkedin and twitter all requesting high priority. Yeah, that just wouldn’t work. As a result, SD-WAN manufacturers have to be smart and identify the application behind the traffic.
SD-WAN devices use Deep Packet Inspection (DPI) or similar technology to identify applications (E.g. salesforce, VoIP, video, data backups, etc.) and then give business applications bandwidth priority over non critical ones to help ensure that the end user experience within an application is optimized. In real time, the traffic for a given flow could be moved from an MPLS connection for example to a 4G LTE connection. SD-WANs support multiple connection types – dynamically!
In theory, all the user has to do is assign the priorities to the applications in one interface and then the SD-WAN controller will do the rest. Policies are pushed out to all the sites participating in the SD-WAN and beyond that, it’s magic. Well, not really. Consumers need a way to keep the SD-WAN vendors honest and some SD-WAN vendors are more open about what is happening than others. Generally, the bigger SD-WAN vendors (e.g. Cisco & VMware) are more open than the smaller ones.
Short comings that I am finding in some SD-WAN vendors:
Nearly all companies with connections to remote offices have or will be deploying SD-WANs. This is as sure as finding a refrigerator in every home. It’s just going to happen. Make sure your company understands the need for SD-WAN and traffic monitoring.
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