"We always say that we are the best-kept secret in the industry," Hui says. "We sit between the user and the server. We improve connectivity."
It is a complex job, not just because of the sophisticated and ever-evolving technology involved, but also because Hui manages nine employees, meets potential customers and handles marketing and administration.
She talks to each of her staff weekly to hear what they have been doing and gathers customer feedback. The most important part of her job is talking and listening to customers, she says, so that she can "understand better what they require and so that I can carry a message to the market".
Hui uses skills she has honed during a career that has exposed her to many different aspects of the industry. After working for British Telecom and AT&T Easylink, she became a sales manager with Dow Jones Telerate, where she learned to read trends and understand how commodity markets work.
Then, at the accounting consultancy firm Arthur Andersen, she worked in risk management and IT governance.
At F5, where she has worked for the past eight years, the focus has changed again.
"It's a very hardware, very engineering type of company. We're very technology-focused. We have more engineers than salespeople."
She behaves like an entrepreneur - innovating, getting feedback and trying out new concepts. Hui says the thought of working for herself does appeal, but she adds: "Once I'm into something, I'm too committed, too focused. The commitment would impact my family."
Family photographs of herself, her husband and their sons, aged 12 and 14, are displayed in her office. She spends as much time as she can with them all.
"I always ask the children, 'do I spend enough time with you?' And they say, 'yes, mum, more than enough'."
She usually has breakfast with the boys, and gets home by 7pm so that the family can eat together. Weekends are mostly family time, but she's usually able to reserve a few hours for reading and yoga. "I like reading a lot - self-improvement [books], novels, Chinese history and world history."
Friday nights are reserved for her husband. "We try every Friday to have dinner, just the two of us," she says.
But, on some evenings, she finds herself opening up her laptop. "I think I'm a workaholic," she says.