Onsite Senior Network Engineer - DoD Voice & UC (TS/SCI)

Castalia Systems; Largo (FL); On-site; USD 120,000 - 160,000; Full time

Benefits offered by this job

Medical, dental, and vision coverage

401k matching

Generous PTO and holidays

Professional training opportunities

Pet insurance

Job summary

Castalia Systems is seeking a Senior Network Engineer for a 100% onsite role in Largo, Florida. You will implement and support network security and voice infrastructure, including CUCM clusters, Unity, and VoIP systems, ensuring compliance with DoD requirements.

You will configure, test, and troubleshoot complex voice networks, manage upgrades, and collaborate with cybersecurity and infrastructure teams to maintain secure communications environments.

Qualifications

• Bachelor’s degree or equivalent with 12 months of relevant experience
• Security+ or CISSP preferred for DoD 8570 IAT Level II
• Strong networking, security, and troubleshooting skills

Responsibilities

• Configure, administer, and maintain CUCM clusters for enterprise and classified environments.
• Manage Cisco Unity Connection voicemail systems and integrations.
• Configure dial plans, SIP trunks, and voice gateways; troubleshoot VoIP infrastructure.
• Provide Tier III support for voice, call routing, and signaling issues.
• Plan upgrades, patches, and lifecycle management for CUCM/Unity Connection.

Skills

CUCM administration

VoIP engineering

Networking fundamentals

Security concepts

Education

Bachelor’s degree in CS/EE or related

Tools

Cisco CUCM

Cisco Unity Connection

UNIX/Linux

Job description

Castalia Systems is seeking a Senior Network Engineer for a 100% onsite role in Largo, Florida. You will implement and support network security and voice infrastructure, including CUCM clusters, Unity, and VoIP systems, ensuring compliance with DoD requirements.

You will configure, test, and troubleshoot complex voice networks, manage upgrades, and collaborate with cybersecurity and infrastructure teams to maintain secure communications environments.