Two-day process with multiple interviews and group exercises. The interview group I was part of included people who had previously interned who had a massive advantage due to knowing company internal structure.
Interview questions [1]
Question 1
Technical questions revolved around algorithms described in an abstract way; good answers required knowledge of how to design and implement efficient algorithms.
Submitted application and was called to interview. Interview consisted of several written timed essays relating to computing and telecommunications, an IQ test, and shown around offices, etc. Also had face-to-face to discuss your answers in the essays. Be sure to know specifics of how networks, etc. work as it helps.