Five-nines is a popular buzzword in the world of network management, and for good reason. With the cost of downtime increasing, network managers are under more pressure than ever to prevent downtime. Everyone wants to achieve 99.999% availability.
However, there are many obstacles on the road to maximum uptime, particularly on an enterprise WAN. Everything from misconfiguration to DDoS attacks to backhoes taking out fiber lines can bring a WAN down. Further, the shift away from MPLS (Multiprotocol Label Switching) to SD-WAN has enterprises concerned with how to guarantee uptime with notoriously unreliable public Internet connections.
In this piece, we’ll dive into the challenges facing enterprises using appliance-based SD-WAN with public Internet connections, and explain how cloud based SD-WAN provides a robust enterprise-grade alternative that maximizes uptime.
Comparing MPLS middle-mile reliability to appliance-based SD-WAN
In legacy WAN deployments, MPLS was the norm. While MPLS has a number of shortcomings today, namely inflexibility, lack of cloud-friendliness, and high bandwidth costs, it has proven effective at delivering reliable “middle-mile” connectivity across telco provided private links. While a reliable middle-mile doesn’t solve all of a WAN’s uptime challenges, it certainly mitigates some of them. For the most part, network managers can trust telcos will provide a reliable middle-mile across MPLS links.
However, with the growth in popularity of appliance-based SD-WAN, things changed. Appliance-based SD-WAN solved many of the cost and agility issues enterprises faced, but it introduced a new wrinkle to maintaining uptime. By shifting away from MPLS to appliance-based SD-WAN, enterprises were moving their middle-mile traffic from leased MPLS lines to the public Internet.
The issue here was simple: performance and reliability on the public Internet is notoriously erratic. SD-WAN features such as PbR (Policy-based Routing) and QoS (Quality of Service) help mitigate some of these challenges. Similarly, leveraging multiple discrete connection methods (e.g. xDSL, cable, 4G) help reduce the likelihood of a complete outage. However, the public Internet simply isn’t reliable enough to expect predictable service on a regular basis. That can be a deal-breaker for many organizations.
While enterprises could use appliance-based SD-WAN with MPLS to help address this problem, that often isn’t an ideal solution. Continuing to use, or shifting back to, MPLS after an effort to move away from the legacy solution is an unattractive fix. Doing so erodes many of the benefits enterprises gained by making the shift to SD-WAN in the first place.
Understanding last-mile uptime challenges
While MPLS was fairly dependable across the middle-mile, the last-mile (the stretch of connectivity to/from the last provider “hop” from/to the traffic’s destination) proved to be a different story. In the last-mile, MPLS coupled with a load balancer can achieve active-passive failover functionality. Generally, this resulted in loss of connections for applications like voice and streaming. SD-WAN leveraging the public Internet could be configured similarly.
How cloud based SD-WAN improves reliability in the middle-mile and the last-mile
Premium cloud based SD-WAN solves the middle-mile problem by providing a global SLA-backed private backbone. The backbone consists of Points of Presence around the globe connected by multiple Tier-1 ISPs (Internet Service Providers). Curious what the SLA for the connections is? You guessed it! 99.999%.
With this backbone, cloud based SD-WAN solves the middle-mile problem appliance-based SD-WAN faced. As opposed to traversing the public Internet for the duration of transport, traffic is sent across the SLA-backed backbone until it reaches the Point of Presence closest to the destination. From there, it is routed over last-mile links to its endpoint.
However, this seems to beg the question: what about the last-mile? Fortunately, cloud based SD-WAN has the last-mile covered as well. Premium cloud based SD-WAN supports features like:
Active-active failover- With active-active failover, two last-mile links are run simultaneously. Intelligent cloud-native software helps load balance across the links. In the event one fails, the other picks up where it left off. This failover occurs fast enough to keep a voice call or videoconference running.
Intelligent last-mile management (ILMM)- Cloud based SD-WAN providers leverage cloud-native software to proactively monitor for network blackouts and brownouts. It can be easy to overlook brownouts because few monitoring solutions detect them, but remember if performance degradation is severe enough, an application or service is effectively down. Additionally, pinpoint identification of the root cause of problems improves mean time to recover in the event downtime does occur.
Coupled with the middle-mile benefits of the private network backbone, cloud based SD-WAN delivers end-to-end network optimization to maximize overall network uptime.
Cloud based SD-WAN helps enterprises maximize uptime
As we have seen, appliance-based SD-WAN is limited by the fact it does not include an underlying network backbone. Cloud based SD-WAN helps enterprises resolve this problem by way of a global SLA-backed backbone that in many cases outstrips even MPLS performance. Further, SD-WAN overcomes last-mile uptime challenges with active-active failover, self-healing features, and intelligent last-mile management. By bundling all these features together, cloud based SD-WAN enables enterprises to minimize the risk of downtime and inch ever closer to the elusive goal of “five nines”.
