Ever since software-defined wide area networking (SD-WAN) has been introduced and become available back in 2014, there has been a debate on whether it is actually better than Multiprotocol Label Switching (MPLS). While SD-WAN is clearly a more modern approach, both still have their pros and cons and are better for certain scenarios.
In case you missed it, Multiprotocol Label Switching (MPLS) technology has been around for a while and it is a par of packet-switched network design which allows packet prioritization. As it does not depend on a specific OSI layer service, it is described as a layer 2.5 protocol and supports different types of traffic, including standard IP packets, native ATM, SONET, and Ethernet frames.
Software-defined WAN (SD-WAN), on the other hand, is a more modern approach, and promises reliability of an MPLS network design but with an ability to dynamically share and aggregate multiple ISP Internet and WAN connections.
Both MPLS and SD-WAN have their certain advantages and disadvantages and we will try to point out at least some of them.
Depending on the actual usage scenario, MPLS biggest advantage is the reliable delivery of packets as well as better Quality of Service (QoS) for important traffic. In scenarios where real-time protocols, like VoIP, video conferencing or virtual desktops, are used, reliability is quite important as it ensures there is no big packet loss.
Since MPLS uses unique labels, also known as MPLS headers, it is considered more secure as well. Although usually much more expensive, MPLS is also simpler for enterprises as most details are handled by the provider.
Unlike MPLS, SD-WAN improves packet delivery by using the Internet and any other network, which could lead to unwanted packet loss. While this can somewhat be remedied by using two Internet links or tools like the Forward Error Correction (FEC), it still needs a lot of work in order to apply QoS and prioritize certain packets.
On the security side, SD-WAN has an ability to establish VPNs, which adds a certain level of security. While it still needs a lot of configuration it can easily be more secure than MPLS, especially since security does not depend on the provider.
Essentially a lot cheaper than MPLS, SD-WAN also needs a lot configuration but since it is done internally, enterprises need a skilled IT service that will take care of the managing and configuration.
While both have their certain advantages, SD-WAN with its lower cost, scalability, control, visibility and an ability to use any type of Internet connection or even mixed network links, is slowly taking over. On the other hand, with reliability in mind, MPLS still has its place on the market.
In some cases, both MPLS and SD-WAN can be used together in a so-called Hybrid SD-WAN configuration which pretty much brings the best from both worlds and is usually used for setting up branch offices or two geographically separated WANs.