Telecom/Computing Engineer (development, operation and evolution of VoIP services) (IT-CS-TR-2020-67-LD)

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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 an experienced service manager with a strong background in designing and developing distributed systems? Would you like to take an active part in running and evolving CERN’s VoIP-based telephony services? Then join our dynamic team of telecom and IT professionals! CERN, 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 4,000 of which with 10Gb/s interfaces, and external connections including multiple trans-border 100Gb/s circuits. The Group also operates its own fixed telephony system (12000 lines), dedicated mobile telephony services (6500 subscriptions), a TETRA digital radio system (500 terminals) and a LoRaWAN network.

More information on the IT Department can be found at:


As a member of the Telecom and Radio (TR) Section in the CS Group, you will participate in the development, operation and evolution of CERN’s VoIP (Voice-over-IP) telephony infrastructure and services.

Your main functions will include:

  • Contribute to the design, development, integration and maintenance of telephony services based on Open-Source solutions (Asterisk/Kamailio).
  • Participate to the phase-out of CERN’s legacy analogue and ISDN telephony infrastructure and its replacement by state-of-the-art, SIP-based mobile and desktop softphone applications.
  • Lead the development and deployment of call centre applications for CERN’s control and service centres.
  • Ensure the proper integration of these services within the CERN’s Puppet-based Agile Infrastructure and DevOps tools.
  • Participate to 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.
  • Produce procedures and documentation following the ITIL recommendations to be used by technicians and engineers in operational activities.


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


The candidate 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 management and operation of scalable, Linux-based, multi-tier web and back-end services.
  • Proven experience in the field of complex systems integration involving legacy systems.
  • Experience deploying services within cloud-native virtualised environments.
  • 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 and operation of VoIP services using Asterisk, Kamailio, FreeSwitch or OpenSIPS.
  • Experience in the management and operation of legacy VoIP systems (such as Alcatel OmniPCX).
  • Experience in application testing, deployment and debugging on mobile Android/iOS environments.
  • Experience in the design and operation of complex IP-based networks.

Technical competencies:

  • Knowledge of communication technologies and protocols: hands-on knowledge of VoIP protocols such as SIP, SDP, RTP and webRTC.
  • Knowledge of / experience with Asterisk, Kamailio, FreeSwitch or OpenSIPS would be an advantage.
  • Knowledge of programming techniques and languages: extensive knowledge of Java and/or Python, shell scripting, JavaScript.
  • Knowledge and application of software life-cycle tools and procedures: git and automated build, testing and packaging; agile methodologies like Scrum.
  • Administration of computing systems: in-depth knowledge of Linux (such as RedHat / CentOS distributions).
  • Design of databases/repositories: experience with relational databases (MySQL, Oracle) and schema modelling.
  • Architecture and design of ICT systems: design, development and operation of highly available services via Openstack, Kubernetes, or Openshift.

Behavioural 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.
  • Communicating effectively: expressing opinions, ideas and suggestions with conviction and in a logical/structured manner; keeping to the point; ensuring that information, procedures and decisions are appropriately documented.

Language skills:

  • Good knowledge of English is required; 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 14.06.2020

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:

  • A valid driving licence is required.
  • Work during nights, Sundays and official holidays, 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-2020-67-LD

Benchmark Job Title: Computing Engineer

Please make sure you have all the documents needed to hand as you start your application, as once it is submitted, you will not be able to upload any documents or edit your application further

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Geneva, GENEVA, CH

Genève , Switzerland