For decades, network engineering was the cornerstone of, well… everything. Without a predictable and reliable network, business stumbled. Network engineering prevented that from happening. No wonder Gartner says the typical enterprise spends 10 percent of its overall IT budget on networking.
Like so much of IT, though, network engineering grew out from our need to overcome constraints. In most cases, we’ve been able to use technology to overcome our limitations. Moore’s Law finally caught up with business computing requirements, giving us “just enough” processing power.
The same was true with storage. We held our breath until storage capacity reach the per square inch and I/O operations per second that could meet our requirements.
But no constraint has been as persistent networking. Getting high-capacity, high-quality and affordable connectivity at a global scale has long eluded businesses.
Network engineers made the best of this bad situation. They squeezed every cent from the MPLS capacity, calculating optimized routes to global or regional data centers. Optimization appliances were deployed to squeeze even more out of those thin MPLS pipes. And inexpensive internet links were added, not MPLS links (where possible), in case a failure should happen when dealing with a flurry of configuration changes. And the engineers did all of that using obscure command line interfaces (CLIs). It was bad enough that MPLS was expensive, but precisely because of the lack of bandwidth, MPLS operations became challenging.
Elimination of that complexity has become a driving force behind traditional SD-WANs. The SD-WAN proposition is enticing: aggregate cheaper Internet capacity, easy deployment, and get rid of legacy MPLS networks. SD-WANs build an overlay across services, masking their specifics from applications. By dynamically routing traffic based on link quality, availability, and application requirements, SD-WANs make multiple data services appear as one single network.
And with fat Internet pipes, SD-WANs avoid much of the engineering needed with MPLS. Network engineering is further minimized because SD-WANs simplify and automate much of traditional network operations. Rather than achieving application delivery by configuring devices and working through redundancy configurations, SD-WANs allow IT to specify tolerances and objectives, and leave the details to the SD-WAN.
In short, SD-WAN seems like the answer to IT’s dilemma — inexpensive bandwidth, predictable delivery, global scale, and it frees up valuable engineering resources. From a cost-benefit standpoint, customers gain from WAN agility and avoid MPLS costs. What more could IT want?
But to replace MPLS, SD-WANs must extend globally, and relying on the Internet was never a serious option. Despite being around since the dawn of large scale computing, the Internet was not designed to be the ultimate global networking platform. It’s loosely coupled design, a collection of public and private entities with often conflicting interests, has promised “best effort” networking – at most. For many businesses, best effort wasn’t good enough.
Within well-developed Internet regions, these limitations might be less noticeable. SD-WANs can avoid convoluted routing, high packet loss at carrier exchanges and more by selecting another route or service provider. But sending traffic across long distances, between Internet regions or areas serviced by only one Internet provider, and traditional SD-WANs stumble. The predictability gap between the Internet and MPLS is just too great. SD-WANs end up augmenting, not replacing, legacy MPLS, making their immediate ROI far less obvious.
To take on MPLS services, SD-WANs need to extend globally, providing routing control, packet loss and latency guarantees everywhere. This is not an easy task to accomplish because it requires a new type of carrier — one that provides affordable, predictable and global connectivity. But done right and with an SD-WAN, enterprises gain a unified network with tremendous amounts of bandwidth and optimal access to all resources: WAN, Internet and Cloud.
We can use any ISP, give branches however much capacity they require, connect to any resource – and eliminate MPLS. So many challenges addressed by network engineering get solved, automatically.
Network engineering is moving out of the black hole of grunt work like many IT disciplines that migrated to the cloud. While the days of CLI might be coming to an end, the modern enterprise faces enormous challenges in the areas of optimal access to cloud applications, securing and integrating cloud infrastructure and enabling business continuity for a highly distributed business. Surely, this will be a large enough task for network engineers that will yield significant return for the business.