The ongoing pandemic and a seismic shift in the number of people working from home has put a new emphasis on SD-WAN. There's just one problem: this explosion in demand, coupled with an already strained supply chain, means many companies are having to wait weeks for the hardware they need.

However, unlike many industries suffering from supply shortages and manufacturing delays — the semiconductor, server, and storage markets to name a few — SD-WAN isn't nearly as straight forward. SD-WAN supply chains vary from vendor to vendor depending on how the platforms are architected and sold. Some SD-WAN platforms may rely heavily on branch hardware, while others use user agents and centralized appliances or cloud instances. And that's before accounting for black-box vs. white-box hardware.

According to Ben Niernberg, EVP at managed service provider MNJ Technologies, many of the supply chain challenges facing the SD-WAN market come down to timing and geography.

He explained that COVID-19 hit China hard starting in December, forcing manufacturing plants to close. "There was two, three months of no productivity coming out of there," Niernberg said.

By the time the virus reared its head in the U.S., many companies, including MNJ, were already running low on equipment, and the Chinese plants were only starting to reopen. Once MNJ went through its inventory and supply started becoming scarce, that's when lead times started to creep up, Niernberg said.

"We've had to talk with customers about being much more proactive about when they are ordering network infrastructure gear and giving us enough lead time," he said.

However, the situation seems to be improving as new cases of COVID-19 decline and the Chinese economy restarts, Niernberg said. "While there's definitely still delays, you're starting to see inventory free up," he explained.

According to Sanjay Uppal, SVP and GM of VMware's VeloCloud business unit, some VMware SD-WAN appliances are on backorder due to supply chain challenges. "As a result, we are extending the option to update existing orders with different appliances where inventory is more readily available," he wrote in an email to SDxCentral.

And while not specific to SD-WAN, Cisco also reported COVID-19-related supply chain challenges during its third fiscal-quarter of 2020 earnings call, earlier this month.

"COVID-19 did have an impact on our financial results and business operations this quarter, especially in our supply chain where we saw manufacturing challenges and component constraints," Cisco CFO Kelly Kramer said during the call.

However, not every vendor has experienced supply chain challenges.

During Fortinet's Q1 2020 earnings call, CFO Keith Jensen reported no problems with supply chain during the quarter. "Our product backlog was in line with historical averages and our suppliers delivered over 90% of their commitment to us," he said.

This is despite the company being one of very few that designs its own networking and security ASICs, which are pivotal to its hardware-centric SD-WAN offering.

"The ability to directly manage our supply chain, shipping, and logistics allowed us to quickly adjust to the current dynamic environment," Fortinet CEO Ken Xie explained.

This, however, may have more to do with Fortinet's ability to handle massive numbers of VPN connections than it does with supply chain.

Fortinet CMO John Maddison, in an earlier interview with SDxCentral, explained that the company's enterprise and data center firewalls can support tens of thousands of concurrent VPN connections, something that few competitors can claim. He explained that this has enabled many of its customers to support the transition to a remote workforce much faster and often without the need for a dedicated agent or additional hardware, except where security within the home may be required.

SD-WAN vendors relying heavily on uCPE hardware, such as Versa, may also have had an advantage over black-box vendors.

"Versa is in a unique position because our Versa Operating System runs on Versa appliances, certified white-box devices, Dell VEP devices, and in virtualized environments, giving our customers a range of diverse options," wrote Versa CMO Mike Wood, in an email to SDxCentral.

According to Wood, while some customers have slowed purchases, many have accelerated their digital transformations, driving increased demand for Versa SD-WAN appliances. However, he noted that while this ramp in demand hadn't been anticipated, Versa's suppliers haven't given any indication of being unable to fulfill orders.

That said, it should be noted that CPE vendors aren't immune to supply chain shortages either. Silicom, during its Q1 2020 earnings call in late April, reported that the pandemic slowed its supply chain, interrupting manufacturing and deliveries.