Ciena's interview process consisted of 2 + 2 rounds.
The first 2 rounds had basic introduction about myself and the company. Initially, their main focus was on Computer Networks and CS Fundamentals. As Ciena, is a core networking company, so having a solid knowledge of Computer Networks is a must.
Then started the main Technical Rounds.
Technical Round 1 :-
I was asked to introduce myself, then basic C++/C and DSA Questions were asked such as Reverse Linked List, Find Loop in Linked List, Set ith bit of a number if not set.
Then i was asked to explain any 1 of my project and my internship experience.
Interviewer also asked me a puzzle (10 Coins Puzzle). Then, he asked me how i can apply my Mathematics knowledge (as my branch was Mathematics & Computing) to build AI products or ML models.
Technical Round 2 :-
Then after around 30-40 mins, i had my 2nd Technical Round scheduled. This time there were 2 Interviewers.
I was asked questions about C, C++, OOPs in-depth covering topics such as polymorphism, inheritance, static, const, virtual keywords, diamond problem, dynamic memory allocation in C, V-table.
Then one of the interviewer wrote an OOPs code and asked me to print it's output or determine if this will give compile/runtime error.
Interviewers also gave me a DSA Problem - Delete kth Node from a Linked List. Everything was pen-paper based. I had to write code on paper.
This round lasted around 50-55 mins.
Verdict : Rejected
Took this rejection as a redirection and started working on my CS Fundamentals and knowledge of Programming Languages.
Suggestions:
Computer Networks knowledge should be solid if you are appearing for any hardware role or Embedded C role.
Otherwise, for application developers, C/C++, OOPs knowledge is required.
Prepare all basic DSA Questions, and have a good understanding of programming languages, OOPs and CS Fundamentals (especially CN).