Outcome
A complete number-routing map, call-flow diagrams and a decommissioning checklist — plus a disaster-recovery path that would have silently failed.
The problem
The organisation wanted to retire both its primary and DR SBCs and move to a carrier’s cloud calling service. Years of accumulated configuration meant nobody was sure what was still live.
What I did
- Parsed both SBC configuration exports into a complete number-to-destination routing table, with sequence diagrams for every call-flow pattern.
- Found leftover configuration for retired platforms, unused test numbers still wired to a routing group, one rule shadowed by a higher-priority rule, and an exact duplicate.
- Discovered the DR SBC still pointed at the previous carrier — never updated at the original cutover — meaning failover would not have worked.
- Cross-checked the Teams tenant: voice routes matched the SBCs, but a single global routing policy sat alongside multiple regional dial plans, and a set of accounts were in a misconfigured hybrid state.
Result
A decommissioning checklist with clear blockers, clean-up items confirmed safe to remove, and a broken DR path caught before it mattered.