One of the many consequences of the coronavirus is that networks are going to see a shift in busy hour traffic. Busy hour traffic is just what it sounds like—it’s the time of the day when a network is busiest, and network engineers design networks to accommodate the expected peak amount of bandwidth usage.

Verizon reported on March 18 that in the week since people started moving to work from home that they’ve seen a 20% overall increase in broadband traffic. Verizon says that gaming traffic is up 75% as those stuck at home are turning to gaming for entertainment. They also report that VPN (virtual private network) traffic is up 34%. A lot of connections between homes and corporate and school WANs are using a VPN.

These are the kind of increases that can scare network engineers because Verizon just saw a typical year’s growth in traffic happen in a week. Unfortunately, the announced Verizon traffic increases aren’t even the whole story since we’re just at the beginning of the response to the coronavirus. There are still companies figuring out how to give secure access to company servers, and the work-from-home traffic is bound to grow in the next few weeks. I think we’ll see a big jump in video conference traffic on platforms like Zoom as more meetings move online as an alternative to live meetings.

For most of my clients, the busy hour has been in the evening when many homes watch video or play online games. The new paradigm has to be scaring network engineers. There is now likely going to be a lot of online video watching and gaming during the daytime in addition to the evening. The added traffic for those working from home is probably the most worrisome traffic since a VPN connection to a corporate WAN will tie up a dedicated path through the Internet backbone—bandwidth that isn’t shared with others. We’ve never worried about VPN traffic when it was a small percentage of total traffic—but it could become one of the biggest continual daytime uses of bandwidth. All of the work that used to occur between employees and the corporate server inside of the business is now going to traverse the Internet.

I’m sure network engineers everywhere are keeping an eye on the changing traffic, particularly to the amount of broadband used during the busy hour. There are a few ways that the busy hour impacts an ISP. First, they must buy enough bandwidth to the Internet to accommodate everybody. It’s typical to buy at least 15% to 20% more bandwidth than is expected for the busy hour. If the size of the busy hour shoots higher, network engineers are going to have to quickly buy a larger pipe to the Internet, or else customer performance will suffer.

Network engineers also keep a close eye on their network utilization. For example, most networks operate with some rule of thumb, such as it’s time to upgrade electronics when any part of the network hits some pre-determined threshold like 85% utilization. These rules of thumb have been developed over the years as warning signs to provide time to make upgrades.

The explosion of traffic due to the coronavirus might shoot many networks past these warning signs, and networks start experiencing chokepoints that weren’t anticipated just a few weeks earlier. Most networks have numerous possible chokepoints—and each is monitored. For example, there is usually a chokepoint going into neighborhoods. There are often chokepoints on fiber rings. There might be chokepoints on switch and router capacity at the network hub. There can be the chokepoint on the data pipe going to the world. If any one part of the network gets overly busy, then network performance can degrade quickly.

What is scariest for network engineers is that traffic from the reaction to the coronavirus is being layered on top of networks that already have been experiencing steady growth. Most of my clients have been seeing year-over-year traffic volumes increases of 20% to 30%. If Verizon’s experience is indicative of what we’ll all see, then networks will see a year’s typical growth happen in just weeks. We’ve never experienced anything like this, and I’m guessing there aren’t a lot of network engineers who are sleeping well this week.