Product Knowledge (Installation, Configuration, Operations, Maintenance)

• Asterisk (deep): Strong operational and development-level understanding of Asterisk internals, especially large and complex dialplans with business logic.
• Dialplan engineering: Ability to design, refactor, and troubleshoot multi-branch call flows, failover paths, and edge-case routing behavior.
• Call encryption: Practical handling of TLS and SRTP in production, including certificate lifecycle and interop troubleshooting.
• SBC stack: Solid Kamailio skills for SIP routing/policy and RTPengine operation for media anchoring, NAT traversal, and media security.

SIP Capture and Troubleshooting

• PCAP and Wireshark: Confident packet-level troubleshooting for SIP, RTP, SRTP, TLS handshake issues, retransmissions, and one-way audio.
• Homer SIP capture: Efficient use of capture/visualization to correlate signaling and media events across distributed components.
• End-to-end call tracing: Ability to correlate identifiers (Call-ID, tags, branch params, dialogs) across Asterisk, Kamailio, and SBC layers.
• Test strategy depth: SIP integration tests, regression suites for dialplan logic, and synthetic call monitoring in production-like environments.

Operating System and Automation

• SUSE Linux (LPIC-1 level or higher): Comfortable with package/service management, networking, process control, and system diagnostics.
• Python (basic): Scripting for automation, validation, and lightweight operational tooling.
• Cron and shell scripting: Building and maintaining jobs for log rotation, housekeeping, health checks, and routine maintenance tasks.
• Log and filesystem hygiene: Managing retention, rotation policies, and storage pressure under high call volume.

Network and VoIP Foundations

• TCP/UDP deep understanding: Behavior under packet loss, reordering, retransmissions, and impact on signaling/media quality.
• VoIP protocols (deep): SIP, RTP, SRTP, TLS, mTLS, codec negotiation, DTMF transport, NAT and firewall implications.
• SIP protocol internals (RFC-level): Transaction/dialog state machines, timers, forking, early media, PRACK/100rel, session timers.
• Network services (deep): DNS behavior (including latency/caching/failover effects), NTP sync relevance for logs/traces, and routing basics.
• High availability and disaster recovery: Active-active/active-passive design, failover testing, backup/restore drills, RTO/RPO ownership.

AWS and Infrastructure as Code

• Core AWS: EC2, VPC, Route 53, Security Groups, CloudWatch, and basic Lambda usage.
• Resilience testing: AWS FIS basics for controlled fault injection and validation of failover behavior.
• Secrets and access management: IAM least privilege, secret rotation, certificate/key lifecycle, and auditability.
• Terraform: Versioned, repeatable infrastructure provisioning and safe change workflows (plan/review/apply discipline).

DevOps and Reliability (Mandatory for Dev + DevOps Collaboration)

• CI/CD pipelines: Build, test, security checks, and controlled release promotion.
• Observability operations: Metrics, logs, traces, and alert tuning to reduce noise and improve incident response.
• Incident response: Structured triage, rollback decision-making, and post-incident analysis.
• Release and change governance: Blue-green/canary strategy, maintenance window practices, and backward-compatible migration planning.