About this role.
Five9 is seeking a Senior Telecom Engineer to support and operate a global cloud contact-center voice network. The role centers on VoIP, SIP, RTP, session border controllers, carrier interconnects, incident response, and service-quality troubleshooting in a 24/7 production environment. The engineer will work directly with customers, carriers, vendors, and the Network Operations Center while contributing to deployments, documentation, root-cause analysis, and preventative improvements. Success requires strong telecom protocol knowledge, hands-on packet and RTP analysis, Linux administration capability, and clear communication during critical service events.
Role DNA
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Job Complexity
4/5Pace & Pressure
4/5Autonomy Level
4/5Communication Load
5/5Salary analysis
Estimated compensation compared with the broader US market for similar roles.
Core skills
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Sample interview questions
I would first define the scope by identifying affected customers, carriers, regions, call directions, and time windows. I would review alarms and relevant SBC, proxy, and media-server logs, then capture signalling and RTP where appropriate. I would assess packet loss, jitter, latency, codec negotiation, RTP path symmetry, and MOS-related indicators before isolating whether the issue is internal, customer-side, or carrier-side. I would document findings, implement or coordinate remediation, and complete a root-cause review if the issue is material.
I would validate dial-plan normalization, routing priorities, least-cost routing rules, number-format handling, carrier interoperability requirements, and failover behavior. I would also ensure security controls such as TLS, IPSEC where applicable, ACLs, trusted peer definitions, and fraud protections are correctly applied. Finally, I would test normal, failure, and edge-case call flows in a lab or controlled environment before production deployment.
I would acknowledge and validate the alert, assess customer and service impact, and use established runbooks while gathering evidence from monitoring, logs, and recent changes. I would communicate status early to the NOC and relevant stakeholders, escalate to carriers or internal teams when ownership is clear, and prioritize safe restoration of service. After recovery, I would verify stability, record the timeline and corrective actions, and contribute to root-cause and prevention work.
A signalling problem is typically visible in failed registrations, malformed messages, unexpected SIP response codes, authentication failures, or incorrect routing decisions. An RTP issue may occur even after successful call setup and is identified through one-way audio, no audio, packet loss, jitter, latency, codec mismatches, NAT behavior, or incorrect media anchoring. I correlate SIP call identifiers with RTP stream captures and SBC/media-server logs to establish where the call flow or media path breaks.
I would begin by confirming technical requirements, number formats, codecs, SIP transport and security settings, routing rules, capacity, failover expectations, and test cases. I would configure the connection in a controlled environment, conduct interoperability testing for inbound, outbound, emergency, failure, and media scenarios, and capture evidence of successful results. After a reviewed production rollout, I would monitor the connection closely, document the design and operational procedures, and address any post-launch issues with the partner.
Join us in bringing joy to customer experience. Five9 is a leading provider of cloud contact center software, bringing the power of cloud innovation to customers worldwide.
Living our values everyday results in our team-first culture and enables us to innovate, grow, and thrive while enjoying the journey together. We celebrate diversity and foster an inclusive environment, empowering our employees to be their authentic selves.
To complement our rapid growth, we are actively sourcing for an experienced Senior Telecom Engineer to join our cloud operations organization on a full-time basis. The ideal candidate is someone who has worked in a 24/7 production support environment and has a strong working knowledge of VoIP, SIP, and RTP.
This position is based anywhere in the UK.
Key Responsibilities
- Interface directly with customer’s telecom engineers and IT teams to deploy customized solutions and trouble shoot issues;
- Assist int the day-to-day operational support of the Telecommunications network, analyzing problems affecting network availability and customer quality reports;
- Escalation point of contact for the Network Operations Center to resolve critical alerts generated by the SBC’s Analyze history of telecommunication related incidents and perform preventive measures;
- Assist in the day-to-day operation of the telecommunications network, where necessary analyzing problems affecting network availability and customer/vendor service quality;
- Provide root-cause analyses on service outages;
- Respond to Telecom alerts and alarms and provide corrective actions in coordination with the Network Operations Center;
- Create technical documentation and call flow drawings as needed Manage Telecommunications Service Provider & Vendors Implement hardware and software deployments on the telephony network as required;
- Deploy new services including interop testing with telecom carriers and customers;
- Provide emergency assistance and technical recovery in the event of an emergency situation affecting the availability and/or service quality of the network;
- Participate in on-call emergency rotation.
Requirements
- 3-5 years of telecom engineer experience with VoIP/SIP voice applications.
- Must have a detailed, working and theoretical knowledge of voice and data communications, including traditional switching, signaling and routing systems to include SIP, TCP/IP, MPLS etc.
- Experience with ribbon SBCs and PSX.
- Working knowledge of VoIP principles, protocols and CODECs such as H.248, SIP, G.711, G.729, WebRTC, MPLS, VPN, UDP, RTP, MTP etc.
- Knowledge of SIP call routing, Least Cost Routing, Security Controls (TLS, IPSEC, ACLs) with Session Border Controllers.
- Knowledge of telecom principals and terminology including DIDs, Toll Free numbers, LATA OCN and NPA-NXX etc.
- Experience with International Routing including ITFS, iDID’s and local termination policies Ability to build, interop and maintain direct connect SIP Trunks to customers and carriers.
- Review, Assess, Critique and Implement Telecom Architecture design changes in Lab and Production environments.
- Excellent organizational and follow-through skill sets are essential.
- Ability to document, troubleshoot and resolve a multifaceted and complex Global voice network.
- Maintain the telephony environment to assure delivery of Cloud applications, voice and customer connectivity and availability to target 99.99% SLA.
- Experience with Softswitch, Session Border Controllers (preferably Sonus/Ribbon, Audio Codes), SIP proxies, Media Servers (preferably AudioCodes IPM-6310 and FreeSWITCH).
- In depth knowledge of Wireshark, Empirix or other network protocol analyzers Ability to capture and analyze RTP streams as related to voice quality traditional KPI’s such as MOS, Jitter, Latency, Packets Loss.
- Ability to execute and use intermediate level Linux/Unix system administrator commands.
- Excellent working knowledge of telecommunications, maintenance processes and systems.
- Proven ability to resolve complex issues in an efficient and timely manner and provide clients with consultative explanations and advice.
- Self-starter with excellent troubleshooting skills and ability to prioritize tasks and organize workflow accordingly.
- Excellent verbal and written communication skills are required Excellent documentation skills are required.
Five9 embraces diversity and is committed to building a team that represents a variety of backgrounds, perspectives, and skills. The more inclusive we are, the better we are. Five9 is an equal opportunity employer.
View our privacy policy, including our privacy notice to California residents here: https://www.five9.com/pt-pt/legal.
Note: Five9 will never request that an applicant send money as a prerequisite for commencing employment with Five9.
Annual salary information is not provided for this position. Explore salary ranges for similar roles in our Salary Directory ›
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