PLAYER ONE

IOANNIS XENOFONTOS

PORTFOLIO

WORLD 01

Experience

Hilton Grand Vacations
Jul 2022 – Present · Orlando, FL

Aug 2026 – Present

Sr. Telecommunications Administrator

Engineer and deploy multi-site enterprise telephony and contact center solutions, including call routing, IVR logic, and ACD configurations.
Implemented 63 production telecommunications changes in 2026 year to date, with formal risk assessment, testing, rollback planning, and implementation validation.
Resolved 679 production incidents in 2026 year to date—approximately 18% of the telecommunications organization’s resolved incidents.
Execute telephony cutovers, migrations, and platform upgrades; implement and validate failover configurations and maintain technical documentation.
Develop and debug custom scripts using .NET-based and C# Snippet language, and diagnose API integration issues through root cause analysis and vendor coordination.
Troubleshoot SIP, RTP, SBC, carrier, connectivity, and call-quality issues in partnership with network and security teams.

Jan 2025 – Aug 2026

Telecommunications Administrator

Administered contact center environments, maintaining user access, telephony settings, call routing, and contact center configurations.
Investigated connectivity, audio quality, and routing issues with carriers, vendors, and internal IT teams.
Implemented approved configuration changes and supported platform upgrades, validating functionality and addressing post-deployment issues.
Maintained call flow diagrams, configuration documentation, and change records.

May 2024 – Jan 2025

Contact Management System Lead Analyst

Trained and mentored seven junior staff members in system administration, troubleshooting, and escalation procedures.
Led daily Contact Management System operations as the primary escalation point for system performance, enhancements, and incident resolution.
Coordinated upgrades, patches, and customizations with vendors and internal IT teams, translating business requirements into technical improvements.

Jul 2022 – May 2024

Contact Management Systems Analyst

Supported hardware, software, and network troubleshooting across an environment of 12,000+ devices.
Created and maintained 1,800+ end-user accounts, managing credentials, access permissions, and licenses across onboarding, role changes, and offboarding.
Managed escalations for major service disruptions across departments, coordinated incident resolution, and documented troubleshooting findings.

View my LinkedIn profile

SELECT A BUILD

Projects

SECURITY LAB

Azure Honeypot & Security Monitoring Lab

AzureSecurity Monitoring

SIMULATED SECURITY ASSESSMENT

Simulated Internal Active Directory Penetration Test

Active DirectoryPenetration Testing

PLAYER PROFILE

About Ioannis

Hi, I’m Ioannis Xenofontos.

I work in telecommunications, with a professional focus on cybersecurity. My work in infrastructure and systems operations provides a practical foundation for that focus, supported by automation and scripting.

This Minecraft-themed site is an interactive extension of my professional resume, with selected security labs and projects.

Visit my GitHub

INVENTORY

Skills

Telecommunications & Infrastructure Engineering

Primary professional focus.

Cybersecurity

Security monitoring and simulated security assessments.

Systems & Production Operations

Systems and operational infrastructure.

Automation & Scripting

A supporting competency for engineering and operations.

FIELD NOTES