Is SD-WAN really a replacement for MPLS?

This question has troubled many IT managers, CTOs and Network Administrators in this era of digital transformation.

Next Generation Network connectivity is a major cog in the wheel of digital transformation for organisations seeking to thrive in the digital economy. There is not a doubt that Wide Area Networks (WANs) continue to serve the needs of the distributed enterprise but

MPLS

To answer this, let’s go back to the basics of WAN connectivity. What is MPLS? Contrary to what you might think, it’s not a service or a type of internet connection, it’s a technique for interconnecting distributed branches.

The service is a managed Virtual Private Network (VPN) usually routed through the service provider network infrastructure. The main benefit of MPLS is that traffic is routed through a private data network (unlike internet traffic) which enables the ISP to guarantee a high end-to-end Quality of Service (QoS) which is usually backed by a binding SLA.

MPLS excels at managing and avoiding packet loss, jitter and latency thus injecting predictability to business traffic flows. MPLS also offers traffic prioritisation, which ensures that your most critical traffic is handled with the highest priority and with the least likelihood of being dropped.

For organisations running real-time applications over the WAN such as VoIP, video conferencing or virtual desktops, MPLS is the holy grail of network connectivity due to its predictability and reliability. MPLS also introduces operational efficiencies for the distributed enterprise with centralised ICT operations where all branch traffic has to be backhauled to the HQ over the WAN.

SD-WAN

Now let’s focus on SD-WAN; an abbreviation for Software-Defined Networking in a Wide Area Network, which finds its basis in software-defined networking (SDN).

SD-WAN overlays intelligence into traditional WANs by decoupling the underlying hardware and software thereby permitting central network control, traffic management and network automation.

SD-WAN allows enterprises to use several transport services to interconnect the WAN, including broadband internet, 4G LTE or even MPLS. A VPN will be set up across each WAN connection to establish a multi-connection, multi-transport hybrid WAN infrastructure.

The embedded intelligence allows organisations to build application-aware networks that improve application performance and enhance user experience especially for businesses hosted in the cloud since traffic does not have to be backhauled to the HQ data centre.

SD-WAN can also securely and intelligently direct packets to the best WAN link and improve business productivity. Its main advantage is its multi-connection capabilities, which reduce the time and cost of deploying WAN links, especially in remote locations, all while avoiding vendor lock-in.

Verdict

All this sounds great, but which of the two is right for your business? Consider this; Does your business run real-time applications? Does it operate from the cloud?

For real-time applications, SD-WAN overlaid on internet links might not measure up against MPLS connections because once traffic hits the public internet, you can’t guarantee low levels of packet loss, latency or jitter.

For businesses running cloud-based applications such as Office365 or Salesforce; or for organisations with cloud environments in AWS or Azure, cloud-enabled SD-WAN offers numerous benefits such as dynamic routing and intelligent traffic steering which enhance application performance. Zero touch deployments also accelerated deployment times thus enhancing business productivity.

SD-WAN can overlay inter-branch and branch-cloud connectivity with security, achieving end-to-end encryption, and best path selection over the internet. However, there are no performance guarantees. But if your business has specific connectivity requirements and needs SLA-backed performance guarantees, MPLS might be better suited for the job.

Conclusion

The MPLS vs SD-WAN debate should be held within the contextual boundaries of the environments you’re working in, the network traffic definition and the specific needs of your business.

If your business requires a high-performance and reliable WAN architecture, you should consider a hybrid of both solutions. Remember that SD-WAN is a transport-agnostic overlay that can route any type of traffic, including MPLS.

With all that said, is SD-WAN really a replacement for MPLS? In my opinion, not really.

To discuss your company’s individual needs and what service might best suit you, speak to your enterprise WAN architect.