Freeze one call and the ordered service state
Record local and UTC time, calling and called numbers, direction, call or ticket identifier, supplier, order, service identifiers, Gamma SIP Trunk, Call Manager and Inbound entitlement, assigned peers, access path, PBX node, portal role, rule version and intended destination. Preserve the failed attempt and the first successful comparison before changing routing.
Classify the earliest divergence: no provider attempt, wrong number assignment, wrong product or rule, request misses the customer edge, PBX rejects or misroutes it, continuity does not trigger, capacity is exhausted, SDP disagrees or media flows incorrectly.
Identify which product owns the route decision
For the affected number, establish whether the intended behavior belongs to the SIP trunk, SIP Trunk Call Manager or a Gamma Inbound service. Retain the order and current portal evidence. Do not apply a brochure feature to a trunk-only service or assume an Inbound destination controls a Call Manager rule.
Map the exact path from number inventory through the selected service to the assigned trunk, alternate destination and PBX. Mark every shared address, circuit, firewall, SBC, PBX node, power source and provider or partner support boundary.
Prove the rule, schedule and destination that evaluated
Capture the active rule name, priority, day or date schedule, timezone, busy, no-reply or failure condition, pass-through or destination, hunt or queue membership and fallback. Compare the incident time with the effective schedule and retain the change audit where available.
A saved rule, portal preview or selected mobile destination is configuration evidence. Confirm the provider attempt, destination ringing, answer and final outcome separately; also check whether an unconditional or higher-priority rule bypassed the expected branch.
Test continuity as a sequence of new-call states
With provider approval, observe the primary path, trigger one bounded failure and retain the first subsequent call, later calls, alternate destination, recovery and return to primary. Separate site-to-site trunk rerouting from Call Manager and Inbound redirection. Do not claim that an established call survives unless the exact call demonstrably remains connected.
Compare the incident against the current Gamma status channel and the customer edge. A clear public status page does not prove the access circuit, assigned peer, customer firewall, PBX or number route is healthy; a listed incident does not prove it caused the captured call.
Rule out identity, capacity and media defects
Preserve Request-URI, To, From, asserted identity, diversion history, SIP responses and the PBX route selected. Then compare ordered and active channels, simultaneous calls, access bandwidth and PBX limits. A busy or rejected call may invoke a different rule without proving the primary network path failed.
Retain SDP offer and answer, selected G.711 or G.729 form, packetization, DTMF and RTP endpoints. Diagnose signaling, route selection and both media directions independently; do not use an answered call as proof of usable audio or general compatibility.
Correct only the demonstrated boundary and retest
Change one verified number assignment, rule, schedule, destination, trunk mapping, PBX route, capacity setting, firewall policy or media field under the documented owner. Record old and new values, approval, propagation, rollback and the exact retest. Avoid restarting multiple systems before the first divergence is preserved.
If evidence remains ambiguous, escalate through the correct direct-customer or partner path with service ID, timestamps, calling and called numbers, provider response, redacted signaling, rule snapshot, status observation and PBX result. One successful retest is not a universal availability, pricing or compatibility result.
Sources & applicability
Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.
- Gamma SIP Trunks and Call Management ↗
- Gamma SIP Trunking user support and training ↗
- Gamma Inbound Call Routing user support and training ↗
- Gamma help and support ↗
- Gamma service status ↗
- Gamma codes of practice ↗
- Gamma Business Communications Code of Practice ↗
- Gamma disaster-recovery planning article ↗
Examples require adaptation to your topology. No live PBX or hardware testing is claimed.