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Computing / Telecom Engineer (VoIP/IoT services) (IT-CS-TR-2021-114-LD)

Geneva, Switzerland
Closing date
15 Nov 2021
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Job Details

Company Description

At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. Using the world's largest and most complex scientific instruments, they study the basic constituents of matter - fundamental particles that are made to collide together at close to the speed of light. The process gives physicists clues about how particles interact, and provides insights into the fundamental laws of nature. Find out more on

Job Description


Are you a talented Computing or Telecom Engineer with a keen interest in developing and evolving scalable distributed communication systems? Would you like to take an active part in evolving CERN’s quickly growing Voice-over-IP and Internet-of-Things services? Then join our dynamic team of telecom and IT professionals, take part!

The Communication Systems (CS) Group is responsible for all aspects of network and telephony provision at CERN. We support a campus network (cabled and Wi-Fi) with over 50,000 connected devices, a 5Tb/s non-blocking switching fabric for a data centre with over 10,000 servers, more than 4000 of which with 10Gb/s interfaces, and external connections including multiple cross-border 100Gb/s circuits. The Group develops and runs a softphone-based telephony system (expanding to 10,000 users) and an IoT network using LoRaWAN and LTE (over 10,000 devices). Furthermore, the Group manages dedicated mobile telephony services (6500 subscriptions) and a TETRA digital radio system (500 terminals).

More information on the IT Department can be found at:


Within the Telecom and Radio (TR) Section in CS Group, as a part of a team of experienced Computing and Telecom engineers, you will take key responsibilities within the development, operation and evolution of CERNs VoIP (Voice-over-IP) telephony and IoT (Internet of Things) services. In particular, you will:

  • Deliver continuous improvement in the design, development, integration and maintenance of CERN?s VoIP based telephony service (CERNphone) that is based on industry-standard Open-Source components such as Asterisk, Kamailio and Flask on the server side, and Linphone and Electron / WebRTC clients on the client side.
  • Drive the design, development, integration and maintenance of the LoRaWAN / LTE based IoT network service, built on top of ChirpStack and RabbitMQ.
  • Take an active role in the phase-out of CERN’s legacy analogue telephony infrastructure.
  • Participate in daily service management, which includes building and deployment of software packages, performance and availability monitoring, fault analysis and correction, as well as providing engineering-level support.
  • Define procedures and deliver documentation to be used by technicians and engineers in operational activities.


Master's degree or equivalent relevant experience in the field of computer science, telecommunications or a related field.


You should have demonstrated practical experience in several of the following areas:

  • In-depth and hands-on experience in the development, deployment and maintenance of highly-available, clustered distributed computing infrastructures based on open-source packages.
  • Experience in the development, management and operation of scalable, Linux-based, multi-tier web and back-end services within bare-metal and container virtualised environments (Docker/Openshift).
  • Demonstrated experience in the software development life cycle: unit testing, continuous integration, version control.
  • Good knowledge of SQL, database systems, and their integration with Java/Python based applications.

Experience in one or more of the following would be an asset:

  • Experience in the development of VoIP client and back-end applications, and/or in deploying VoIP services (Asterisk, Kamailio).
  • Experience in the development and operation of IoT services based on LoRaWAN and/or cellular networks.
  • Experience in developing web-based application packages on Windows, Linux and macOS.
  • Experience in application testing, deployment and debugging on mobile Android/iOS environments using Android Studio / XCode.

Technical competencies:

  • Development of application software: design and implementation using REST-based APIs/microservices; frameworks such as Flask, React, Electron. Design of state-of-the-art UX/UI interfaces. Integration with monitoring services (Grafana, InfluxDB).
  • Knowledge of programming techniques and languages: advanced knowledge of Python, shell scripting, JavaScript, Java, CSS/HTML.
  • Architecture and design of ICT systems: design, development and operation of highly available services via Openstack, Kubernetes, and/or Openshift would be an advantage.
  • Knowledge of communication technologies and protocols: VoIP protocols such as webRTC, SIP, SDP and RTP and solutions such as Asterisk and/or Kamailio. LPWAN technologies such as LoRa, LoRaWAN, LTE-M, NB-IoT and solutions such as ChirpStack and/or TTN would be an advantage
  • Knowledge and application of software life-cycle tools and procedures: agile methodologies like Scrum/Kanban, version control tools like git.
  • Administration of computing systems: advanced Linux knowledge, ideally with RedHat / CentOS distributions would be an advantage.
  • Design of databases/repositories: experience with relational databases (MySQL, PostgreSQL, Oracle) and schema modelling.
  • Capturing and analysis of requirements for ICT systems: working with end users to understand their needs and provide corresponding technical solutions.

Behavioral competencies:

  • Solving problems: seeking and integrating other points of view when tackling an issue; consulting experts in the field and undertaking benchmarking.
  • Achieving results: delivering prompt and efficient service taking into account customer needs.
  • Working in teams: building and maintaining constructive and effective work relationships.
  • Learning and sharing knowledge: keeping up-to-date with developments in own field of expertise and readily absorbing new information; sharing knowledge and expertise freely and willingly with others; coaching others to ensure knowledge transfer; thinking "out of the box" and proposing fresh ideas, insights and methodologies.
  • Communicating effectively: demonstrating a pro-active approach to resolving differences; addressing issues of conflict constructively; delivering presentations in a structured and clear way; adjusting style and content to the audience; responding calmly and confidently to questions.

Language skills:

Spoken and written English. Ability to draw-up technical specifications and/or scientific reports and to make oral presentations. Basic knowledge of French or an undertaking to acquire it rapidly.

Additional Information

Eligibility and closing date:

Diversity has been an integral part of CERN's mission since its foundation and is an established value of the Organization. Employing a diverse workforce is central to our success. We welcome applications from all Member States and Associate Member States.

This vacancy will be filled as soon as possible, and applications should normally reach us no later than 15.11.2021 at noon CET.

Employment Conditions

Contract type: Limited duration contract (5 years). Subject to certain conditions, holders of limited-duration contracts may apply for an indefinite position.

These functions require:

  • Work in Radiation Areas.
  • Interventions in underground installations.
  • A valid driving licence is required.
  • Work during nights, Sundays and official holidays, when required by the needs of the Organization.
  • Shift work, when required by the needs of the Organization.
  • Stand-by duty, when required by the needs of the Organization.

Job grade: 6-7

Job reference: IT-CS-TR-2021-114-LD

Benchmark Job Title: Computing Engineer


Imagine taking part in the largest scientific experiment in the world. CERN needs more than physicists and engineers – if you’re a student, a graduate, just starting your career or an experienced professional, Whatever your field of expertise, CERN could be your next opportunity: take part!

CERN is a truly unique organisation. A genuine collaboration between countries, universities and scientists, driven not by profit margins, but by a commitment to create and share knowledge.

People here are part of immense scientific discoveries, answering some of life’s most complex questions and pushing the boundaries of understanding. Experts from every field come here to share in this ambition and the nature of this collaborative, international community creates a genuine atmosphere of trust. People are free to work creatively and to trust in, and rely on, their colleagues across the organisation.

History’s being made here – and the excitement is tangible, inspiring, overwhelming at times. It is the only place in the world that you can do this work in this way.

CERN. Take part.

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