Juniper Networks Interview Experience For Internship (On Campus)
Question Details
Juniper Networks visited our campus to hire interns. The company visited our campus to recruit Software Development Engineer (SDE) interns with strong proficiency in C/C++...
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Juniper Networks visited our campus to hire interns. The company visited our campus to recruit Software Development Engineer (SDE) interns with strong proficiency in C/C++ programming and a deep understanding of networking. Firstly, there was an online round, after which 54 people were shortlisted for further procedures which included two technical rounds, 1 managerial Round, and the Last round was HR.
Online Round The total time for the test was 90 minutes during which we were given 20 mcqs based on aptitude(mostly quantitative), dbms, operating systems, and data structures along with three coding questions. MIXINS (Only Python was Allowed) : Mixin classes help add any additional functionalities to some classes using multiple inheritances. Implement two classes DictMixin and JSONMixin, that add a function to_dict and to json respectively. They should convert a Python class to a dictionary and JSON. They should only convert object attributes that do not start with (underscore). If some class is not convertible to JSON, raise a TypeError with the message "Object is not JSON serializable" (without quotes). SINGLE INSTANCE (Only C++ was Allowed): Implement a class Single instance, which contains an integer variable value with a getter and setter for the same. It should have the property that prevents the creation of more than 1 instance of the class at any time.. Another instance can be created when the previous one is deleted. if an attempt is made to create a second instance, it class should throw an exception with the message "Couldn't create more than 1 instance of SingleInstance. ROW MAX (Only C was Allowed): A 3D array of 4x2x3 was given. Dynamically allocate the memory for the 3D array having height h, r rows, and C columns using threads. Assign values to the allocated matrix. For each of the h 2D arrays, find the row with the greatest number of 1's. Break ties with the lowest index row. If there are no 1's,
return -1.
Returns: int maxRows[h]. 1st Technical Round. This Round was virtual and total 54 students were shortlisted for this. For me, It lasted for 35 mins. The questions asked: Introduce yourself 10 mins about projects and internship Write c code for Macro for bit for a given position. Bit position starts from 0. In the output, if bit is 0 output should be 0 and if bit is 1 output should be 0. Write a function for finding middle of linked list Write code for power of 2 numbers.(
example if two numbers are 2 and 4 output should be 2 power 4) What is Smtp protocol, how it works through OSI layer What are vlans and Its application Arp and DNS protocol and some basics questions regarding networking 2 Technical Round This Round was Face to Face and total 30 students were shortlisted for this. For me, It lasted for 1 Hour. The questions asked: Introduce yourself 10 mins basic questions on projects How much you rate yourself in C/C++ out of 5 Explain how boot process in PC works How compiler works in the background Differentiate between C and C++ Why C is used more in embedded systems, though C don't have OOPS support why vectors use more space than arrays. Write a code for finding loop in the Linked list(explain with diagram) Write a c++ code for finding second largest element in an array. Write a code for pointer to a function Which data structure is used for dictionary based applications Which is the optimal sorting technique. Explain merge sort with code and diagram If "Hello" packet is sent through OSI model, tell how it goes through each layer of model and how the packet will be visible if it is viewed from physical layer What is Wireshark tool and its benefits What is process and threads What is multiprogramming in Operating system Why mutex and semaphore used in Operating system 3rd Round (Manegerial) : This Round was again a virtual and total 20 students were shortlisted for this. For me, It lasted for 40 mins. The questions asked: Introduce yourself How was your day? Are you interested more on scripting languages or development languages ? Explain something about your projects Write a function for reversing a Linkedkist and explain by taking the example Given a 32 bit integer and position. Write a function to perform set and unset on it 2 snippets were given and identify the error in it. If there is error, Tell what message compiler gives and which lines give errors. Later they explained my job role and working of Juniper networks and tools I should learn before joining the company. 4th Round (HR): This round was Face to Face, and only 14 peoples were shortlisted for this round including me The questions asked: Introduce yourself briefly If not c/c++, networking what job you were looking to join Any certificates for networking? Why Juniper? Do tou have any plans for masters? Did tou came to banglore earlier? How is Banglore How much you rate yourself in programming skills? Can you leave web development skills for this role?(as my projects were on wedbev) What are your expectations at Juniper Networks? 5 mins talk on Hobbies, that I mentioned in my resume. 5th Round (3rd Technical Round): This was the special round for me only out of 14 students who cleared HR. This round lasted for 20 mins. The questions asked: Introduce yourself How much you rate yourself in c/c++ Explain and write a code for dangling pointers What is const pointer and pointer to const Name all layers in network and tell important protocols of each layer Gave a python snippet: A=[1,2,3,4] B=A C=[1,2,3,4] ---- i)A is B ii) B is C iii) A==C. Out of this which lines will throw error while interpreting. Which are your favorites subjects in the engineering and what are the subjects you currently studying in the 7th sem? If many routers and connected each other, and you want shortest path to travel to each router- which data structure can be used? Puzzles on 2 dice ( how can we get all numbers from 0 to 31, if 2 dice of 9 faces were thrown together) Why you are interested on this role, though you have great projects and internships on web development? At last, explained each department of Juniper networks, how working will be done, what are the tools they use most, more details about their client. In the exclusive interview round tailored specifically for me, I unfortunately did not get the internship opportunity at Juniper Networks. 13 other individuals, Excluding me, were selected for the internship. While I may have felt unlucky at the time????, I also recognize that this experience was valuable and enriching.
About This Question
This is a reported interview question from a juniper networks interview for a data science role (intern level) during the phone screen round reported in 2023.
It covers the following topics: Linked List, Arrays, Sql, Sorting, Os, Graphs, Hash Table, Matrix .
Difficulty rating: Easy
Topics
About Juniper Networks Interview Reports
This question was reported by a candidate who interviewed at Juniper Networks. LeakCode aggregates interview reports from 10+ sources, including 1Point3Acres, Glassdoor, LeetCode Discuss, Blind, Reddit, Indeed, and Nowcoder. Each report is translated where necessary, deduplicated against existing entries, and tagged by company, role, round type, and reporting date.
Use this question as one calibration data point, not a memorization target. Companies typically rotate their question pools every 2-4 months; the exact wording of a 2024 question may differ from what you encounter today. The underlying pattern, difficulty level, and follow-up depth at Juniper Networks are the higher-signal extractions to take from this report.
For broader preparation context, the Juniper Networks interview process typically includes a recruiter screen, one or two technical phone screens, and a 4-5 round on-site loop covering coding, system design (at L4+ levels), and behavioral. Reports tagged on LeakCode show the round-by-round distribution and typical difficulty calibration. To browse questions filtered by round type and seniority, use the company hub linked above.
How To Practice This Type of Question
Solve similar problems on LeetCode under timed conditions (25-35 minutes per medium difficulty). The goal is pattern recognition: recognize the underlying technique (sliding window, two-pointer, BFS, memoized recursion, etc.) within 60-90 seconds of reading. Strong candidates verbalize their hypothesis out loud before coding, then iterate based on feedback. Weak candidates dive into implementation immediately, lose time on the wrong approach, and run out of time for follow-ups.
Companies update their question pools every 2-4 months. The exact wording of any given question may have been retired by the time you interview. Focus your prep on the pattern, not the specific problem. The patterns that appear in Juniper Networks reports consistently are the ones worth investing in; one-off niche problems are not.
During Your Juniper Networks Round
Apply the standard interview round template: clarify requirements (2-3 minutes), state your approach out loud and confirm direction with the interviewer (3-5 minutes), code with narration (15-25 minutes), test with concrete examples including edge cases (5 minutes), discuss optimization or trade-offs if time permits (5 minutes). This template is universally accepted across FAANG and adjacent companies; deviating from it produces weaker interviewer feedback signal.
The single most predictive failure mode in Juniper Networks reports tagged "no hire": not asking clarifying questions. Interviewers are explicitly trained to weight this. Strong candidates ask 3-5 clarifying questions even on problems that look obvious; weak candidates dive into code immediately. The clarifying-question check is often the first signal recorded in the interviewer's written notes.