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Will edge routers be replaced as SD-WAN growth continues?

SD-WAN growth is affecting the edge router market, according to Gartner forecasts. Network expert Andrew Froehlich discusses whether or not SD-WAN will replace edge routers.

Can software-defined WAN replace your edge router? This question becomes more prominent as SD-WAN growth continues to rise. The answer is more complex than one might think. The reason for this complexity resides in how one defines an edge router -- and how it differs from software-defined networking, or SDN, as a whole.

Let's first look at what most people consider edge routers. Strictly speaking, an edge router is a specialized hardware appliance that sits at the various boundaries of a LAN. In most cases, enterprises maintain an internet edge, as well as a WAN edge. The role of an edge router is to connect to external resources outside of the LAN to route data in and out.

SDN is the concept of separating the data plane from the control plane. Generally speaking, the data plane forwards packets from one network device to the next. The control plane acts as the intelligence that dictates optimal paths a data packet will flow between source and destination devices. In SDN, the centralized control plane provides end-to-end network visibility, which adds additional benefits in choosing the most efficient data path. This contrasts with traditional edge routers that maintain data-path intelligence on a hop-by-hop basis.

Edge router appliances face results of increasing SD-WAN growth

We've defined traditional edge routers and SDN, and we know SD-WAN growth is on the rise. Now, we can better answer whether SD-WAN will replace edge routers. From a hardware-appliance standpoint, the answer is yes. Soon, we'll no longer have dedicated router appliances at our network edges.

Instead, commodity hardware will be used in its place to perform data-plane duties. The control plane will be centralized within the corporate LAN -- or in the cloud -- to provide intelligent path selection. All WAN routing, intelligent path selection and application optimization will occur within the same control plane system of the SD-WAN architecture.

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This was last published in February 2017

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