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INTERVIEW GUIDE

Cisco Software Engineer Interview: Questions & Process

Cisco's software engineer interview blends standard data-structure coding with CS and networking fundamentals (OS, TCP/IP, OOP) and a genuine focus on culture. It's generally less of a LeetCode-hard grind than FAANG — expect a recruiter screen, a technical phone screen, and 2-4 onsite rounds mixing coding, fundamentals, and behavioral, with team fit weighing heavily.

The interview process

1. Recruiter screen — ~30 min call
Tests: background, interest in Cisco and the team, logistics and timeline
2. Technical phone screen — 45-60 min
Tests: one or two DSA problems plus questions on your projects and core CS concepts
3. Coding round — 45-60 min live coding
Tests: arrays, strings, linked lists, and OOP design — clean, working code over exotic algorithms
4. CS & systems fundamentals — 45-60 min
Tests: operating systems, networking (OSI/TCP-IP, sockets), concurrency, and how your projects work under the hood
5. Behavioral / team fit — 45 min
Tests: collaboration, ownership, communication, and alignment with Cisco's culture-first values

Questions you're likely to get

Technical

  • Given an array, return the indices of the two numbers that add up to a target.
  • Check whether a string of brackets is validly balanced.
  • Reverse a singly linked list, iteratively and recursively.
  • Merge two sorted linked lists into one sorted list.
  • Find the contiguous subarray with the maximum sum.

Role-specific

  • Walk me through what happens, end to end, when you type a URL and hit enter.
  • Explain the difference between TCP and UDP and when you'd choose each.
  • What's the difference between a process and a thread, and what is a race condition?
  • Design a set of classes to model a network device and its interfaces (OOP design).

Behavioral

  • Tell me about a project you're proud of and your specific contribution.
  • Describe a time you worked through a conflict with a teammate.
  • Tell me about a time you had to learn something new quickly to finish a task.
  • Why Cisco, and what about our culture appeals to you?

Practice these problems live

Relevant LeetCode problems for the Cisco Software Engineer loop. Start a live, AI-run coding interview on any of them — or open the problem on LeetCode.

▶ Two Sum· Easy · LeetCode #1
Two Sum is a common easy opener that checks basic hashing instincts.
▶ Valid Parentheses· Easy · LeetCode #20
Valid Parentheses tests clean stack usage, a frequent Cisco warmup.
▶ Reverse Linked List· Easy · LeetCode #206
Reverse Linked List is a classic pointer-manipulation question they like.
▶ Merge Two Sorted Lists· Easy · LeetCode #21
Merge Two Sorted Lists checks careful linked-list handling without tricks.
▶ Maximum Subarray· Medium · LeetCode #53
Maximum Subarray separates brute force from a clean linear scan.
▶ Number of Islands· Medium · LeetCode #200
Number of Islands adds a manageable graph-traversal step for stronger candidates.

How to answer (worked examples)

Explain what happens when you type a URL and hit enter.
Walk the layers in order so it reads as networking fluency: DNS resolution, TCP handshake (and TLS if HTTPS), the HTTP request, server processing, the response, and the browser rendering. Mention caching and where it speeds things up. Cisco is a networking company — going one layer deeper than expected (ARP, routing, ports) signals genuine systems knowledge rather than memorized trivia.
Tell me about a project you're proud of.
STAR, but emphasize the technical 'how' and your specific role. Situation/Task: the problem and why it mattered. Action: the design decisions you made and the tradeoffs, since interviewers often drill into the architecture. Result: the outcome and what you learned. Be ready for deep follow-ups — Cisco interviewers probe whether you actually understand what you built.

What Cisco looks for

FAQ

How hard is the Cisco SWE interview?

Generally more approachable than FAANG. Coding problems skew easy-to-medium, and there's more emphasis on CS fundamentals, your projects, and culture fit. It's still rigorous — just less of a pure algorithm gauntlet.

Do I need to know networking?

It helps a lot. As a networking company, Cisco values candidates who understand TCP/IP, the OSI model, sockets, and how systems communicate. You won't always be quizzed on it, but depth here sets you apart.

How much does culture fit matter?

A lot. Cisco emphasizes its 'conscious culture,' and the behavioral round is a real gate, not a formality. Have authentic stories about collaboration, ownership, and why Cisco specifically.

What languages and tech come up?

Depends on the team — C/C++, Python, Java, and Go are all common, with networking and systems teams leaning lower-level. You can usually code in your strongest language.

How long does the process take?

Usually a few weeks, though it varies by team and how quickly scheduling lines up.

Practice the fundamentals out loud

Cisco will ask you to explain TCP vs UDP and walk through your own project under pressure — easy to fumble if you've never said it aloud. Rehearse the coding, the fundamentals, and the culture-fit stories with OfferLoop's realtime voice coach.

Practice this interview out loud →

Related

All Cisco interviews →Cisco Data Analyst interview →Cisco Data Scientist interview →Cisco Data Engineer interview →Cisco Machine Learning Engineer interview →

OfferLoop is an independent interview-practice tool and is not affiliated with, endorsed by, or sponsored by Cisco. All company names and trademarks are the property of their respective owners.

Interview formats vary by team, level and year, and this guide is compiled from general knowledge of publicly discussed hiring processes — treat it as preparation material, not an official description of Cisco's current process.