Small Business / Internet / Enterprise / Networking / WAN

Constructing High Availability Business Internet Connectivity

Rob Rodier
Managers and employees of businesses across all industries and markets today log onto the internet to do their jobs. In fact, many of them couldn’t do their jobs without internet connectivity and a consistently connected office. Disruptions prevent access to cloud infrastructure, Software as a Service (SaaS) solutions, Desktop as a Service (DaaS), Unified Communications (UC), and other services that they’ve come to depend on. Internet service disruptions not only stand in the way of updating databases or answering emails, they can create confusion, inhibit customer engagement, and grind production to a halt.

It’s also worth noting that losing service completely isn’t the only potential problem businesses can experience with internet access. Inadequate speed, bandwidth limitations, and latency can minimize efficiency, harm otherwise positive customer and user experiences, and in general, slow things down.

The Advantages of Redundancy

To ensure they can keep operations running, many businesses and organizations create high availability networks through redundancy – multiple internet connections that are in place if one should fail. Software-defined wide area networks (SD-WANs) and modern firewalls make it easy to monitor, load balance and failover between different connections automatically. When there is a failure or excessive demand on one network, the other manages necessary workloads – and users often never know there have been changes behind the scenes to keep them working.
There are two things to consider with redundant internet access:

1. Physical Diversity
Physical diversity refers to separate physical connections between a building and an internet service provider (ISP). One option for a redundant system connecting both through a telephone company and a cable company. Although those two modes of connecting to the internet don’t share infrastructure, they can, however, be similar enough not to provide adequate redundancy. For example, if utilities are cut off during severe weather or if a traffic accident damages a utility pole, neither physical connection may work.

Other businesses or organizations may have multiple fiber feeds – and may ensure diversity by connecting to the building in different places rather than through a single entry point. If the fiber connections different entry points, the business can ensure that if one is damaged or disrupted that the carrier can reroute traffic via another path. This configuration provides a degree of redundancy, but again, there are scenarios in which internet service can be completely lost.

Another option is to back up wired connectivity with wireless service. Wired broadband adoption is growing, and it can offer very high bandwidth and service levels. Moreover, with the 5G service rollout under way, users will benefit from even faster speeds, more bandwidth, and lower latency. Wireless is a good option for several reasons: LTE is available in most areas, it’s available on pay-per-use models, and most importantly regarding availability, physical connection disruptions are unlikely to interrupt this service.

2. Network Diversity
Unfortunately, sometimes even the most effective physical diversity strategy alone cannot guarantee high internet service availability. The CenturyLink/Level (3) outage is a prime example. In August 2020, traffic dropped nearly to zero, potentially impacting their service across all 50 states. When there is a large issue such as this, carriers that share backbone elements and interconnected points with upstream providers can be impacted. Physical connectivity may still be functional, but internet traffic can’t get through across the public internet.

To maintain internet availability, an integrator can use PeeringDB and ASRank ranking tools to determine networks’ shared elements, peering (the ability to connect and exchange traffic) and routing. This information lets you choose diverse networks with different peering relationships and create true redundancy that results in continued availability if an event, such as the CenturyLink outage occurs.

Also, keep in mind that just because the building that you work out of only has a limited number of access providers (fiber, coax, etc) that you likely are not limited to these companies to order your internet service. In many cases, a carrier with physical access in a building will lease their fiber or transport to another carrier, who can actually become your ISP. This is often done transparently to the end users, with the lit carrier providing physical layer 2 connection that allows the chosen ISP to reach your office. With a little research up front, these options can be architected to optimize availability and routing.

What’s Your Tolerance for Downtime?

In 2014, Gartner conducted often-quoted research based on industry surveys that concluded network downtime, on average, costs $5,600 per minute. This is of course, an average – smaller companies would have less work stoppage and losses from paying labor, fewer customer make-goods and other costs. Then again, that research was performed several years ago, and the average cost could be much higher now.

A key takeaway for businesses is that downtime doesn’t have to be part of the cost of doing business. By choosing to build a high availability system with both physical and network diversity, you can minimize internet service interruptions – as well as interruptions to workflows, production, and communications – and ensure continued connectivity that has become so integral to your business.

Managing and preventing downtime with SD-WAN

SD-WAN adoption has accelerated over the last few years, and one of the reasons for this is that it makes managing and aggregating multiple ISP circuits very easy to accomplish. In fact, many single site enterprises (or multi-site without the need for a WAN) opt to deploy SD-WAN for the sole purpose of providing load balancing and fail over in order to optimize site uptime and internet availability. We spoke about the difference between physical and network diversity above, and SD-WAN can help accomplish both.

Many SD-WAN solutions provide constant circuit monitoring, oftentimes including multiple health checks for packet loss, latency and jitter each second. If the SD-WAN appliance deployed onsite detects an ISP gateway failure, or even degradation of one of the underlying ISP circuits it will automatically reroute traffic to a better path if one is available.

Additionally, there are cloud based SD-WAN solutions that measure all of these same metrics at a local level, but also proxy all of your traffic through their networks. If they detect a network based outage, peering or otherwise between upstream providers they oftentimes have the ability to route around these issues. There is also a short list of SD-WAN providers who will actually assign you public IP addresses from their cloud that your multiple ISPs sit behind. This means that failing over from the fiber connection your phone company provides to the coax connection your cable company provides doesn’t change your public IPs. Bigleaf Networks is one such company and will even demo a VoIP call moving from one circuit to another without dropping, pretty cool!

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