Let’s start by looking at the way we’ve built WAN for the past two-plus decades. Branch offices ,where more than 80% of transactions are handle, business were connected to a headquarters-based data center by a router over a leased line connection-usually MPLS. And that model was fine back then, because all applications were hosted in Interprise Data center. traffic was routed from sources to destination based on TCP IP addresses, access control list table and complex routing protocols all of the control functions was distributed across all the routers.
The traffic patterns have changed with the introduction of applications moving to the cloud, this could be enterprise apps that are now hosted in Amazon web services or Microsoft Azure or Google cloud or software-as-a-service apps like Office 365 Box, Dropbox and even Facebook and more
Sending Cloud traffic that is destined for the internet back to headquarter simply doesn’t make sense. It add delay that degrade application performance and it consumes costly leased line bandwidth.
Why not use the internet to reach apps that are hosted on the internet this has driven the need for more intelligent software-driven or software-define model for the WAN – SD-WAN
SD-WAN (Software Defined Wide Area Network) – A connection service management platform that provides functions of cross-domain networking and value-added services.
Traditional network is based on completely hardware network devices which mostly rely on Multi Protocol Label Switching (MPLS) for resilient and efficient network traffic flow.
Technology Pain Points: