Voice Engineer III

Job Title: Voice Engineer III

Security Clearance: Secret

Location: San Antonio, TX

(Due to the nature of the work and contract requirements, U.S. Citizenship is required.)

C3EL is seeking a cleared and experienced Voice Engineer to join our team on-site in San Antonio, TX. This role provides expert-level support in sustaining, maintaining, and leading Problem and Change Management efforts for DISA’s Voice Services, ensuring secure, resilient, and uninterrupted voice communications across critical DoD networks.

Responsibilities will include, but not be limited to:

• Perform engineering tasks to maintain a large, complex and highly resilient IP voice and video communications infrastructure.


• Manage, configure, troubleshoot and assure service supporting all aspects of a voice, video and data network. Must be organized, document oriented, possess skills in diagramming, and understand WAN principals.


• Perform system maintenance, support capacity planning activities and complete configuration change actions and documentation efforts.


• Configure and implement calling search spaces, route plans, route partitions, route lists and device profiles.


• Configure Cisco or Juniper routing and switching devices.


• Support distributed firewall infrastructure.


• Provide input in the development of technical policy, work instructions and reporting in support of an enterprise IP telephony network.


• Analyze and resolve complex technical problems utilizing foundational knowledge of SIP signaling and call-flows.


• Analyze and resolve remote site registration, signaling and media problems.


• Configure route plans, route lists, device profiles, calling search spaces, and route partitions. 


• Validate change requests and ensure accuracy.


• Perform fault analysis and configuration of voice subscribers, call handlers and call routing rules.


• Perform fault analysis and configuration of Cisco and or Juniper routing and switching rules.

• Working knowledge of Secure Real-Time Transport Protocol (SRTP) including associated G.711 and G.729 codecs and Digital Tone Multi Frequency (DTMF).


• Experience with Cisco Unified Communications Manager and or Avaya Aura soft switches.


• Experience with Oracle SBCs and other voice media gateway appliances.


• Experience supporting distributed firewall infrastructure.


• Experience creating/supporting IPSec MPLS VPN infrastructure.


• Experience implementing and supporting BGP routing protocols.


• Experience designing, configuring and troubleshooting QoS classification, marking and prioritization of network traffic (voice, critical applications, etc.).


• Familiarity with IPSec implementation and troubleshooting.