Despite the broadening appeal of SD-WAN, rumors of MPLS’ demise have been greatly exaggerated.
As we’ve written about before, software-defined wide area networking (SD-WAN) has become increasingly common as enterprises transition to an app-first and cloud-first approach to IT. According to the International Data Corporation, the global SD-WAN market is set to enjoy a remarkable 69.6% compound annual growth rate for the foreseeable future, likely surpassing $8 billion in value as soon as 2021.
However, as we highlighted in our previous discussion, “Longstanding approaches to wide area networking like multiprotocol label switching (MPLS) still have a place in the enterprise space.” We’re diving into a deeper investigation of what MPLS really is and when it represents a better option than newer — and, increasingly, more popular — networking techniques like SD-WAN.
MPLS first emerged in the early 2000s as a way to mitigate the latency inherent to traditional networking approaches. In the early days of enterprise networking, an IP packet carried no information other than the IP address of its ultimate destination. As such, each time an internet router received a packet, it would have to make a forwarding decision based only on the packet’s network-layer header.
The mechanics of these decisions were fairly complex, as routers had to reference sprawling routing tables to determine the most efficient network “hop” a packet could make towards its terminus. This stepwise routing process takes time, meaning a certain amount of latency is effectively built into the system. Such latency was acceptable for most IT operations back in the mid-1990s, but enterprise IT teams started to face significant problems as technologies like video conferencing and voice over IP (VoIP) came into fashion.
To accommodate the demands of these time-sensitive operations, MPLS assigns each IP packet a specific forwarding equivalence class (FEC) as soon as it enters a WAN. Every router in an MPLS WAN is provided with a table that pre-establishes highly efficient routes for each FEC, enabling them to shepherd packets along without having to perform the timely header analysis required by traditional networking approaches. With MPLS, high-priority packets like those that contain real-time video or VoIP traffic can be pre-assigned to low-latency routes, guaranteeing exceptional quality of service.
Admittedly, this quality of service doesn’t always come cheaply. Unlike SD-WAN, MPLS relies entirely on traditional networking architectures comprised of hardware that must be purchased, configured, and managed in-house in order to achieve optimal results.
In environments where this is already the expectation (think enterprise branch offices, college campuses, and large retail facilities utilizing point-of-sale systems), MPLS shouldn’t add a great deal of expense to IT operations. However, for smaller organizations comfortable with the baseline unreliability of the public web (the cornerstone of SD-WAN), the cost of the networking technique may outweigh its potential benefits.
For both sets of organizations, the primary value of MPLS is its guaranteed level of performance. Even with recent advances in SD-WAN technology, it’s still incredibly unwise to run real-time applications — ecommerce transactions, remote desktop programs, instant messaging tools, video conferencing, VoIP, etc. — on anything but an MPLS network.
Ultimately, the MPLS versus SD-WAN debate comes down to a simple risk/reward calculation. If an administrative team is willing to tolerate a moderate degree of latency in a set of operations, a software-defined approach will probably get the job done. If unparalleled performance is the order of the day, however, MPLS remains the only choice.
Regardless of one’s preferred approach, good networking depends first and foremost on proper network construction and skillful network management. That’s why many organizations choose to partner with a networking expert like Turn-key Technologies (TTI) to optimize all of their IT operations. Whether you’re looking for an in-depth network assessment or an ongoing managed services relationship, TTI can tailor our services to any set of unique needs.