SD WAN Versus MPLS: A Detailed Comparison

Introduction to MPLS & SD WAN: 

SD-WAN (Software-Defined Wide Area Network) and MPLS (Multiprotocol Label Switching) are both types of networking technology used to connect remote networks, but they have some key differences. Multiprotocol Label Switching (MPLS) is a technology used to route network traffic using a label-switched-path network model. An MPLS network works to increase speed and control the flow of data packets along pre-defined network paths using specialized hardware routers

A software-defined WAN (SD-WAN) is a large network that connects LANs using software, not hardware. SD-WANs do not require any specialized equipment for routing. They run over the regular Internet, making them cheaper to implement than other networking methods. The SD-WAN model does not exclude the usage of MPLS — MPLS can be one of the networking methods used in an SD-WAN.

SD-WAN Advantages Over MPLS:

No specialized Hardware: SD-WANs do not rely on specialized hardware. MPLS requires configuring specialized routers to forward packets correctly. SD-WANs can run using any networking hardware.

No Inherent Bandwidth Limit:: SD-WANs have no inherent bandwidth limits. Because MPLS connections are more or less set in stone (unless they are reconfigured), there is a hard limit over how much capacity can be provisioned over an MPLS connection at once. SD-WAN connections can add capacity as required by combining multiple connections and leveraging the fastest connectivity available.

Provider Selection Independency: SD-WANs are service provider-agnostic. MPLS requires organizations to use the same carrier at all WAN-connected sites because MPLS connections have to be configured in physical routers in the adjacent network. SD-WAN connections run over the regular Internet; any ISP can support an SD-WAN connection.

Flexible Connectivity Options: SD-WAN routing is more flexible. SD-WAN can take advantage of multiple connectivity options including broadband Internet connections, private lines, and 5G. It can direct traffic and failover between all available connectivity options. MPLS services typically require dedicated private line connections from the service provider.

MPLS Advantages Over SD-WAN:

More Granular Control Over Packets: An MPLS network offers more granular control than an SD-WAN architecture; packets always follow the defined path. Typically, data packets on the Internet take different routes depending on how routers on the path are forwarding packets at that time — but MPLS routes are only updated manually. MPLS packets never deviate from the defined route since they always are forwarded between the same routers and networks. Depending on the routing method used, network traffic on an SD-WAN likely will not always take the same route, and some packets may be lost in transit, as is the case with most Internet traffic.

Sometimes More Reliable: From a performance perspective, MPLS provides a reliable, fixed level of bandwidth. MPLS traffic is usually given a higher priority over service provider backbone networks relative to Internet traffic. MPLS services often include quality-of-service (QoS) guarantees. SD-WAN leverages best effort Internet services and may experience occasional packet loss. However, most SD-WAN services compensate for this by intelligently steering traffic away from lossy connections.

Real Time Application:  MPLS often includes multiple classes of service which are preserved throughout the WAN. This makes it easier to ensure real-time applications have a better experience across the WAN.