Many firms have seen production delayed because of a lack of semiconductors, triggered by the Covid pandemic and exacerbated by other factors.
Cisco chief Chuck Robbins told the BBC: "We think we've got another six months to get through the short term.
"The providers are building out more capacity. And that'll get better and better over the next 12 to 18 months."
That expansion of capacity will be crucial as advances in technology - including 5G, cloud computing, the internet of things and artificial intelligence - drive a big increase in demand.