Got contacted by HR, who introduced me to this opportunity. I decided to apply through a form on their website.
There were 5 stages:
1. CV screening
2. HR phone interview : very professional and easy going interviewer, very nice to chat with. She asked about my cv, studying and experience. Then we talked about my interests and attitude - I had to make real life examples of previous experience to prove I was being honest.
3. Skype interview with System Engineer: again good experience, professional and easy to talk to person. He asked about my academic career, with insight questions on my exams + 2 "technical" questions about networking
4. Skype Manager Interview: toughest, imo. Very specific questions -which required very specific answers- about life experience to test my attitude and approach to working/life stressful situation. Anyway he was again professional and kind. He asked 2 technical questions about networking, too.
5. Final Manager (the one you will work with if he/she agrees to hire you) + Job offer Skype call: more a call than an interview, asked questions about why I wanted to join them and more in general what I am expecting from such an experience.
Questions weren't too technical nor difficult, you just need to review basic telecommunications and networking concepts.