Interview experience
Cisco Interview Questions and Answers (2026)
Overview
Section titled “Overview”Cisco’s fresher loop pairs an online coding test with two technical rounds that probe networking and OS depth, not just DSA.
Cisco interview process at a glance
Section titled “Cisco interview process at a glance”| Round | Duration | What it tests |
|---|---|---|
| Online Assessment (“Code with Cisco” test) | 60-90 min | 30-40 MCQs (OS, DBMS, computer networks, OOP) + 2 DSA problems |
| Technical Round 1 | 45-60 min | DSA problem-solving + detailed project/resume discussion |
| Technical Round 2 | 45-60 min | Networking and CS-fundamentals depth; basic system design for some tracks |
| HR / Managerial | 30-45 min | Motivation, culture fit, relocation, logistics |
Online Assessment / “Code with Cisco” test
Section titled “Online Assessment / “Code with Cisco” test”The screening test runs 60-90 minutes on most drives: a large MCQ section covering OS, DBMS, computer networks, and OOP concepts, plus 2 DSA coding problems (easy-to-medium). Some cycles run this under the “Code with Cisco” branding, a nationwide test Cisco uses for its India campus pipeline.
Common questions
- MCQs on OSI layers, DNS, DHCP, and the difference between switches, hubs, and routers
- OS basics: process scheduling, deadlocks, memory management
- DBMS basics: normalization, joins, indexing
- Reverse a linked list / string manipulation coding problems
Full round-by-round accounts are on the Cisco interview experience page.
Technical Round 1
Section titled “Technical Round 1”A 45-60 minute round focused on live DSA problem-solving, followed by a detailed walkthrough of a resume project - tech stack choices, the hardest bug you hit, and what you’d change.
Common questions
- Detect a cycle in a linked list
- Binary tree level-order traversal
- Explain the architecture and trade-offs of your most substantial project
- Basic OOP questions: polymorphism, inheritance, abstraction with examples
See how candidates actually handled this stage on the Cisco interview experience page.
Technical Round 2
Section titled “Technical Round 2”This round leans further into computer networks and OS than a typical software-company loop, since Cisco’s core business is networking hardware and software. Some tracks add a lightweight system-design or scenario question.
Common questions
- Explain TCP vs UDP, and where each is used
- Walk through what happens when you type a URL into a browser
- Deadlock conditions and how an OS avoids or recovers from them
- A short system-design or scenario question (varies by team and role)
HR / Managerial round
Section titled “HR / Managerial round”The closing round checks motivation, team fit, and logistics rather than technical depth. Managerial variants sometimes fold in a light behavioural question about how you’d approach the role.
Common questions
- Why Cisco, and what do you know about its networking products and culture?
- How would you maximise learning over an internship or first year?
- Are you open to relocation, and what is your notice period?
- Describe a time you resolved a conflict with a teammate
Sample answer frameworks for each of these are on the Cisco HR interview questions page.
Code with Cisco: the campus hiring funnel
Section titled “Code with Cisco: the campus hiring funnel”Cisco’s India campus hiring runs through a distinct funnel rather than a plain walk-in drive. “Code with Cisco” opens a nationwide online test to final-year students at participating colleges; a shortlist of top scorers is then invited to a multi-day, Cisco-sponsored hackathon at its Bengaluru campus (travel, food, and stay covered for finalists). Strong hackathon performance can fast-track candidates toward internship or full-time software-engineering offers, running alongside - not instead of - the standard technical-and-HR loop described above. Treat it as Cisco’s version of a mass campus drive: high volume at the top of the funnel, with the interview rounds still deciding the outcome.
Common technical interview questions and answers
Section titled “Common technical interview questions and answers”Q: Explain the OSI model and which protocol lives at each layer
The OSI model has seven layers: Physical (cables, signalling), Data Link (MAC addressing, framing, switches - Ethernet, ARP), Network (logical addressing and routing - IP, ICMP, routers), Transport (end-to-end delivery - TCP, UDP), Session (connection management), Presentation (encryption and encoding - TLS, JPEG), and Application (HTTP, DNS, SMTP, FTP). The practical TCP/IP model collapses these into four: Link, Internet, Transport and Application. The distinction Cisco interviewers push on is Layer 2 versus Layer 3: a switch forwards frames using MAC addresses within a single broadcast domain, while a router forwards packets using IP addresses between networks and separates broadcast domains.
Q: What is the difference between a hub, a switch and a router?
A hub is a Layer 1 device that simply repeats every incoming signal out of all other ports, so all devices share one collision domain and one broadcast domain - it is effectively obsolete. A switch is a Layer 2 device that learns MAC addresses into a CAM table and forwards a frame only out of the port where the destination lives, giving every port its own collision domain while keeping one broadcast domain per VLAN. A router is a Layer 3 device that forwards between different IP networks using a routing table, and it does not forward broadcasts, so each interface is a separate broadcast domain. The follow-up is usually VLANs - they let one physical switch host multiple broadcast domains, and traffic between VLANs still needs a router or a Layer 3 switch.
Q: Explain TCP versus UDP and the three-way handshake
TCP is connection-oriented and reliable: it numbers bytes, acknowledges them, retransmits losses, reorders segments, and applies flow control through a receive window plus congestion control through slow start and congestion avoidance. UDP is connectionless with just ports and a checksum, an 8-byte header against TCP’s 20-byte minimum, and no delivery guarantee. The three-way handshake establishes a TCP connection: the client sends SYN with its initial sequence number, the server replies SYN-ACK with its own sequence number and an acknowledgement, and the client sends a final ACK - after which data flows. Teardown takes four segments using FIN and ACK in each direction, and the closing side sits in TIME_WAIT for twice the maximum segment lifetime so stray duplicate segments cannot corrupt a new connection on the same port pair.
Q: What happens when you type a URL into a browser?
The browser first checks its own cache, then the OS cache and hosts file, then queries DNS - the resolver walks from root to TLD to authoritative nameserver unless a cached answer short-circuits it - returning an IP address. With the IP, the OS uses ARP to find the MAC address of the next hop (the default gateway if the destination is off-subnet), then opens a TCP connection with the three-way handshake, and for HTTPS follows with a TLS handshake that authenticates the server certificate and agrees on a session key. The browser sends an HTTP GET, the server responds with status, headers and HTML, and the browser parses it into the DOM, fetching CSS, JavaScript and images as sub-resources before rendering. Cisco interviewers usually stop you to go deeper at one specific hop - most often DNS resolution or the routing decision at Layer 3.
Q: How does DHCP assign an IP address?
DHCP uses a four-message exchange remembered as DORA. The client broadcasts a DHCPDISCOVER because it has no address yet, a server replies with DHCPOFFER containing a candidate IP, the client broadcasts DHCPREQUEST to formally accept one offer (broadcast so other servers know their offers were declined), and the server confirms with DHCPACK. The lease carries not just the address but the subnet mask, default gateway, DNS servers and a lease duration, and the client tries to renew at 50 percent of the lease via unicast. Since DISCOVER is a broadcast and routers do not forward broadcasts, a client on a different subnet from its DHCP server needs a DHCP relay agent, configured on Cisco routers with the ip helper-address command.
Q: How do you detect a cycle in a linked list?
Use Floyd’s tortoise-and-hare algorithm: advance a slow pointer one node and a fast pointer two nodes per step. If the fast pointer reaches null the list is acyclic; if the two pointers ever meet, a cycle exists. To find the cycle’s starting node, reset one pointer to the head and advance both one step at a time - they meet at the entry point, which follows from the distance relationship between the head, the loop start, and the meeting point. This is O(n) time and O(1) space, versus a hash-set approach that is also O(n) time but costs O(n) space. Counting the loop length is a follow-up: keep one pointer at the meeting point and walk until it returns.
Q: Perform a level-order traversal of a binary tree
Use a queue: push the root, then while the queue is non-empty pop a node, visit it, and push its non-null left and right children. That visits nodes breadth-first in O(n) time with O(w) space, where w is the maximum width of the tree - which is roughly n/2 for a complete tree, so space is O(n) in the worst case. To group the output by level, record the queue size at the start of each outer iteration and process exactly that many nodes before starting a new level list. Common follow-ups build directly on this: zigzag traversal reverses alternate levels, and the right-side view takes the last node of each level.
Q: What are the four deadlock conditions and how does an OS handle deadlock?
Deadlock needs all four Coffman conditions simultaneously: mutual exclusion, hold-and-wait, no preemption, and circular wait. An OS can respond in four ways. Prevention structurally denies one condition, most practically circular wait by forcing a global lock-acquisition order. Avoidance uses runtime information, as in the Banker’s algorithm, which grants a request only if the resulting state remains safe. Detection lets deadlock happen, runs a wait-for graph cycle check periodically, and recovers by killing a process or rolling back a transaction. The fourth option is what general-purpose systems like Linux and Windows actually do - ignore it, the ostrich algorithm - because prevention costs more than the rare deadlock, while databases use detection and abort one transaction as the victim.
Frequently asked questions about Cisco interviews
Section titled “Frequently asked questions about Cisco interviews”What is the Cisco interview process for freshers?
Cisco’s campus loop usually runs: 1. Online Assessment / “Code with Cisco” test (60-90 min) - 30-40 MCQs on OS, DBMS, computer networks, and OOP, plus 2 DSA coding problems. 2. Technical Round 1 (45-60 min) - DSA problem-solving and a detailed project/resume walkthrough. 3. Technical Round 2 (45-60 min) - networking and CS-fundamentals depth, sometimes basic system design. 4. HR / Managerial (30-45 min) - motivation, culture fit, relocation. End-to-end timeline is commonly reported as 2-8 weeks.
What questions are asked in Cisco interviews?
Expect DSA basics (linked lists, trees, strings), and a heavier-than-usual computer networks section - OSI layers, DNS, DHCP, switches vs routers vs hubs - alongside OS (process/memory management, deadlocks) and DBMS. Technical rounds also dig into your resume project in detail, and HR asks about relocation, notice period, and why Cisco.
How many rounds are there in the Cisco interview?
Typically 4 stages for freshers: Online Assessment, Technical Round 1, Technical Round 2, and HR/Managerial. Experienced-hire loops reported on Blind commonly compress this to a recruiter screen plus two technical rounds and one system-design round, then a hiring-manager conversation. Exact composition varies by team and by hiring cycle.
What is “Code with Cisco”?
Code with Cisco is Cisco India’s flagship campus recruiting funnel: a nationwide online coding test open to final-year students, followed by shortlisting and - for top performers - a multi-day, Cisco-sponsored hackathon at its Bengaluru campus. Strong performers there are fast-tracked toward internship or full-time software-engineering offers, alongside the standard interview loop.
What is the Cisco fresher salary package?
Student reports put fresher India packages in the roughly ₹20-30 LPA range, though this varies by role, location, and hiring cycle. Confirm exact figures on your own offer letter rather than relying on aggregated estimates.
Is Cisco’s process different for freshers vs experienced hires?
Yes. Fresher/campus loops lean on the Online Assessment plus two structured technical rounds and HR. Experienced-hire loops reported on Blind and Glassdoor skew toward a recruiter screen, two technical rounds, and a dedicated system-design round before a hiring-manager conversation - with less emphasis on CS-fundamentals MCQs and more on architecture and prior-project depth.
How should I prepare for Cisco interviews?
Practise timed DSA on arrays, strings, linked lists, and trees; revise computer networks in real depth (OSI model, DNS, DHCP, routing basics) since Cisco weighs this more than most software-only companies; keep one clear project narrative ready; and prepare STAR-style answers for the HR round.