MPLS heads towards retirement as SD-WAN adoption soars

• Multi-protocol Label Switching (MPLS) is being squeezed out of corporate  networks as enterprises adopt SD-WANs.
• Networks will rely more and more on big pipe Direct Internet Access (DIA) services to provide the underlying networking fabric for their WANs. 

Telegeography has been tracking MPLS usage and reports that it has actually dropped by a market-changing 24 per cent over just two years from 2018, as DIA has shot up. A welter of stats from Telegeography reinforce what is clearly a major technology adoption change. 

Today it says, 43 per cent of enterprises had installed SD WAN by 2020, compared to just 18 per cent in 2018 and the adoption curve is steepening. 

The bottom line is that, as SD-WAN and cloud use rises, MPLS use declines, with the average network having it operational at  58% of sites in 2020, compared to 82% in 2018. And the  architecture of what we used to call the ‘wide area network’ is changing. Where before the classic WAN conjured up the image of a network diagram with wide area circuits connecting branch office nodes to a central HQ and data centre, today this ‘network’ is probably best defined by IP pipes connecting an organisation’s various  workplaces to the cloud. 

Balancing cost and performance

One of the important roles for SD-WANs is to allow IP and MPLS to achieve optimum coexistence. MPLS is a data transmission  technique rather than a network type and it was introduced - usually by telcos - to cater for high value, but pernickety network traffic running across (as the name suggests) a multi-protocol network. Using MPLS enabled important data streams and voice conversations to traverse while maintaining reasonable quality by setting up routes at layer two and then switching the packets without having to do address look-ups. 

The common or garden corporate data stream -  probably heading to and from the internet  - could use IP connections to enable bulk traffic to be scaled up as demand for Internet access from the enterprise rose.

At the time of the rise of the SD-WAN -  from about five years ago to now - big changes were already under way for the enterprise network. The increasing number of applications migrating to the cloud mean that high speed Internet access has become even more important.  

“SD-WAN has dramatically increased in adoption in the last couple of years,” says Greg Bryan, Senior Manager, Enterprise Research at TeleGeography.  “The pandemic slowed down roll-outs for a time, but increased interest in adoption.” He added that SD-WAN frees WAN managers to select a broad mix of underlay technologies, and can also boost performance.

According to the Telegeography survey, increasing site capacity and using alternative access solutions are the key motivators for WAN managers pursuing SD-WAN, Direct Internet Access (DIA) was found to be the key underlay product for larger capacity sites, and more than one-quarter of DIA sites were larger than 100 Mbps. 

As with most technology trends COVID-19 has intervened to accelerate change that was already well under way.

When SD-WANs were first being introduced, the narrative (I recall) was that MPLS would remain an important WAN technology, but that IP would play an increasing role as traffic volume increased. 

In reality MPLS has remained comparatively expensive to deploy and support with equipment, while IP has both scaled up and become more capable quality-wise, a trend that if continued, will probably see MPLS earning a well-deserved retirement from most enterprises in the not-too-distant future.