On the Phone interview, I was aksed questions mostly from my resume and background. I was asked quesions on 1. Descrtibe RADIUS protocol in brief 2. Describe the differences between TCP and UDP 3. Describe the end-to-end callflow for one system you worked 4. Threads vs Processes 5. Task scheduling in vxWorks and some more questions based on my resume In the main interview, I had 1:1 with four people spread over the day 1. Describe Pre-emption 2. priorirt Inversion and how to overcome it 3. Interrupts and ISRs 4. How do timers work in vxWorks 5. Semaphores 5. Linked list vs array 7. Trees, BSTs and when to use And other questions were mostly to explain on white board what all I did in my last 10 years..and design details of that and why it was designed that way etc Then some questions on the debugging tools I used like GDB