Went through the Cisco frontend engineer loop about six weeks ago. This was for a role on one of their internal dashboard products, not customer-facing consumer stuff. Wanted to share because frontend at Cisco is a bit different from what you'd expect if you're coming from a startup or FAANG.
The thing that surprised me most: they did not ask me much about React internals. No questions about reconciliation, no hooks trivia, no 'explain the virtual DOM.' They cared a lot more about core web fundamentals.
What actually came up: Browser rendering pipeline: what happens between HTML parsing and first paint. Reflow vs. repaint, why it matters for performance. Accessibility: WCAG basics, ARIA roles, keyboard navigation. They asked me to describe how a screen reader would navigate a modal I described. JavaScript fundamentals: closures, event loop, how async/await works under the hood, call stack vs. task queue. One coding problem: implement a debounce function from scratch. Classic but they watched how I handled edge cases. A take-home / live-coding exercise: build a small filterable table component with sorting. They evaluated code organization more than raw speed.
The system design round was lightweight for my level (mid-senior). We talked about how I'd structure a real-time network monitoring dashboard. Focus was on data fetching strategy (polling vs. websockets), component architecture, and performance at scale with many concurrent updates.
Behavioral: four STAR questions, fairly standard. Conflict with a stakeholder, a time you had to advocate for a technical decision, owning something that failed.
Total: 4 rounds, about 3.5 hrs. They moved quickly once debrief was done, offer in about 10 days.
If you're preparing: nail your JS fundamentals and have a strong answer to 'how do you approach performance optimization.' That came up in two separate rounds.