The first round was a phone screening, where I received a call from the Head of Operations from the Chicago office. This call was mainly about who you are and how much research have you done about the Citadel or Citadel Securities. After a week I was invited for the face to face interview at the London office. The 1:1 interview will have 5 rounds of 45 minutes with a lunch break in between. NOTE: All the time you'll be analyzed for your behavioral skills and smartness. The first round that day was again a screening from a manager who will try to assess if you are the right fit for the role by behavioral analysis, he'll ask questions related to your previous experiences and what skills you have developed from your previous job roles. The next round was with the team lead of the Infrastructure Operations, where he'll explain the job role and will ask you questions like how comfortable are you with windows troubleshooting, Linux scripting (Bash), networking concepts. Also will ask if you are comfortable working in a 24x7 environment. The third round was a technical interview where the interviewer asked questions on networking knowledge (All questions will be related to the LAN, also don't think they have enough knowledge working towards WAN, so answer all the questions from the LAN perspective). The company work mainly on IPV6 and Multicast concepts, so ensure you have brushed up well on the concepts and also subnetting knowledge. Most of the questions will be the situational basis, like how would you connect between your 2 storages between the datacenters, how will you troubleshoot slow connectivity remotely, etc. (NOTE: there are no right or wrong answers for the situational based questions, they are mainly looking into your approach for solution). The next round was a video conference with a person at the Chicago office. This round is only about your CV, they will cross-question every single thing that you have mentioned in your CV, whether it's about your skills or past experiences or your education or even hobbies, so make sure you have not faked your resume. They will also ask why you want to join Citadel and what has made you apply for this role. The last round was again with the manager who took the first round that day. Questions asked in this interview were a kind of summarized questions of all the rounds that day. Every interviewer will give you an opportunity to ask questions, do not miss this opportunity to learn more about the job role, how they work and their personal experience in the company.