As 5G becomes more prevalent, SD-WAN solutions become more reliable and agile
Dozens of companies are providing Software-Defined Wide-Area Networks (SD-WAN), and with that broad range of providers there is an equally broad set of definitions and feature sets available to explore on the topic. The technology has traditionally hinged on intelligent path selection, centralized management of policies, all-in-one design for branch simplification, zero-touch deployments, flexible VPN capabilities, and a replacement for Multiprotocol Label Switching (MPLS). These are all critical to the value that SD-WAN delivers.
However, as LTE and 5G become increasingly ubiquitous and connections become more agile and reliable, it’s valuable to zero in on SD-WAN’s ability to manipulate or control network traffic to ensure a certain outcome and explore how the technology will adapt to this new world of wireless.
A brief history of SD-WAN
Close to a decade old, SD-WAN entered the technology scene when bandwidth usage grew thanks to the explosion of imagery, video, and VoIP. As networks became increasingly complex, a need to replace deterministic routing and MPLS emerged. SD-WAN architecture was developed largely as an augmentation or replacement for MPLS to deliver more responsive, predictable applications at a lower cost by separating network services from applications, thus enabling the network to match the needs of the business.
An SD-WAN router understands that not all applications are the same, not all networks are equal, and the state of the network at any given time might be different. Armed with that knowledge and the policies set forth by the administrator, SD-WAN uses multiple links to establish a more reliable connection and then chooses the best path to achieve a desired outcome. For example, a call center may dictate that inbound calls from their customers are the top network priority, followed by web browsing and email. SD-WAN will then look at the network and ensure those priorities happen through WAN optimization, traffic handling, and link selection.
Although the functions of these SD-WAN solutions remain the same, the technology developed for a hybrid MPLS and broadband network doesn’t necessarily translate to what is needed for a hybrid broadband and cellular (LTE or 5G) network.
The impact of 5G on SD-WAN solutions
As technology evolves, so too must connectivity solutions. The remarkable increase in bandwidth and decrease in latency that comes with the expansion of the 5G spectrum means the following aspects of SD-WAN technology may become obsolete.
Because of its ability to handle significantly more bandwidth compared to cable, much less T1s, 5G makes WAN optimization techniques like caching, compression, and deduplication virtually irrelevant. Minimizing the amount of traffic across the WAN isn’t the overwhelming goal it used to be, yet many SD-WAN solutions are loaded down with WAN optimization techniques developed for a 1.5 Mbps world.
If a single link doesn’t have enough bandwidth on its own to manage the needs of a location, many SD-WAN solutions are able to aggregate small links to form a single, larger link capable of handling more traffic. But with 5G being a massive standalone link, it’s not as important to combine multiple links together to form a larger one. The focus turns to managing traffic across that single link instead of link bonding.
Active/active traffic handling
Similar to link bonding, active/active traffic handling solves for insufficient link capacity by simultaneously using multiple links and can also be used to select specific links for specific applications. However, now that enterprise traffic is increasingly directed to the cloud, the SD-WAN architecture that separates links for different applications becomes less relevant. Also, due to the decreased latency on 5G networks and general improvements in broadband quality and capacity, high-quality links no longer need to be reserved for top-tier applications.
The origins of SD-WAN relied on tunneled technology, because the packets required a connection from one SD-WAN appliance to another. As networks grew, the tunnels started to proliferate and reliance on the tunnel-based system became unrealistic, especially today as more and more traffic is filtered to the cloud over cellular broadband connections. Tunnel-based SD-WAN seeks to recreate a dual-ended datacenter type connection in the cloud, even though traffic is increasingly HTTPS and destined for SaaS locations.
How SD-WAN and cellular co-exist to provide solutions for businesses
While 5G establishes a path of evolution for SD-WAN, it does not replace the need for SD-WAN. WAN diversity is a key principle of SD-WAN functionality; cellular broadband is a crucial component to achieve that diversity. 5G provides a reliable, diverse connection because of its ubiquity, reduced latency, and increased bandwidth. Additional benefits of 5G SD-WAN include:
- Resiliency against accident-induced outages, weather, and natural disasters
- Out-of-Band Management
- Day-1 connectivity and rapid re-establishment
- Broad availability
- Dual connectivity to both 4G and 5G, providing built-in failover
- Consolidated billing
- Strong security
- Network access control
The abilities of SD-WAN to monitor the network for degraded links, prioritize one type of traffic over the other, ensure application quality, compensate for errors in the network, and make decisions during outages have become critical to business continuity — and they are here to stay. However, like any technology, SD-WAN must adapt to changing needs of businesses and a changing technology landscape. 5G as an enterprise WAN link doesn’t remove the need for SD-WAN, and it can enhance the value received from SD-WAN. But this value is maximized by working with an SD-WAN solution that understands 5G and brings two technologies together to build a fast, reliable and agile network.