John Chambers, chief executive at Cisco, has sent an email to employees admitting management failures and indicating the company needs to refocus its efforts.
Chambers said Cisco's strategy was "sound", it was reported. But he added: "It is aspects of our operational execution that are not.
"We have been slow to make decisions, we have had surprises where we should not, and we have lost the accountability that has been a hallmark of our ability to execute consistently for our customers and our shareholders. That is unacceptable."
The Financial Times reported that a fall in confidence had hit Cisco in recent months, particularly as the company expanded into lower-margin activities.
Cisco needed a more targeted strategy, Chambers wrote in his email. "Many say that in the face of this expansion, Cisco needs more discipline. I agree. It's time to focus."
Key areas of focus would include its core network router and switching market, as well as collaboration, video technology and data centre virtualisation.
"In switching we understand that our customers are buying across broader segments and specific needs in this market," he wrote. "We understand that our competitors in this area are fierce, with different business models and architectures."
"Bottom line, we have lost some of the credibility that is foundational to Cisco's success - and we must earn it back."