Cisco Software Development Engineer (SDE) interview questions

They really focus on topics from core computer science subjects like interrupt service routines, deadlocks(asked to code it too), semaphores, scheduling in operating system then from computer networks like role of all the layers, TCP, UDP. Was asked if comfortable in UNIX/LINUX. Few coding questions were asked to like swapping the bit at two given positions. How does recursion happen, like flow of a recursive program, tree traversals.