Freeze one service, site and affected interval
Record UTC and local time, active agreement and order, customer, service location, Granite entity or affiliate, on-net or off-net scope, SIP service form, access, handoff, trunk identity, PBX or SBC version, direction, calling and called values, DTFO state, burst state, first response, alert, answer, audio and hangup. Redact credentials and unnecessary subscriber data.
Preserve the last-known-good time and recent order, access, number, port, capacity, burst, DTFO, E911, PBX, firewall, portal or provider change. Diagnose the first unexpected boundary before editing multiple systems.
Compare the order with the loaded handoff
Use the current implementation record for the exact service form, site, access, trunk, authentication or identification, signaling target, numbers, base call paths, burst terms and DTFO option. Compare those facts with PBX or SBC objects actually loaded and the path actually selected.
Do not copy a realm, address, credential, certificate, transport, port, codec or media range from another Granite order or from the legacy brief. Public product language does not define a universal handoff.
Separate base capacity, burst policy and first response
Record purchased base call paths, documented burst entitlement and ceiling, active dialogs, offered attempts, call-start times, PBX resources, access utilization, first PBX or provider response, destination response and completed calls. Compare the same interval with a bounded ordinary control call without generating unapproved production load.
Distinguish local resource exhaustion, access impairment, provider policy, burst rejection, destination busy, timeout and a completed call. A portal counter or invoice item does not by itself prove the runtime owner.
Verify DTFO trigger, target and alternate delivery
Confirm that DTFO is ordered for the affected trunk or number block, then preserve its documented trigger, current target, activation state and test authorization. Align primary-path impairment or exhaustion evidence with provider redirection evidence, alternate-edge receipt, PBX route, answer and both media directions.
Do not use an ordinary forward as proof of DTFO. An alternate answer does not establish outbound recovery, established-call continuity, media quality or primary-path restoration.
Trace number, SIP, SDP and both media directions
For inbound failure, follow number order or port state, provider attempt, delivered called value, edge receipt, PBX match, alert and answer. For outbound failure, retain selected trunk, calling identity, dialed value, request, response and destination result. Then align SDP, interface packets, NAT or firewall state, decoding and each listener result.
An accepted INVITE, loaded route or packets in one direction do not establish usable two-way audio. Change only the first demonstrated owner.
Correlate E911, SLA and bounded restoration
Confirm the jurisdiction-specific emergency record, registered location, callback number, notification recipients, PBX route, power and access dependencies without an uncoordinated live emergency call. Retain the Granite portal service object, ticket, on-net or off-net scope, severity, response, provider finding, action and any credit request separately.
After one authorized correction, repeat the affected ordinary call, an unaffected control and DTFO validation only under an approved plan. A response objective, case closure, credit, alternate answer or one successful call does not establish root cause or durable restoration. No Granite service, burst, DTFO event, emergency result, incident or support finding was tested for this diagnostic.
Sources & applicability
Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.
- Granite — VoIP & Cloud Phone Systems ↗
- Granite — SIP Trunking brief (legacy, date-scoped) ↗
- Granite — Legal & Policy ↗
- Granite — General Terms of Service (May 2026) ↗
- Granite — VoIP Services Additional Terms and Conditions of Service ↗
- Granite — VoIP Services Service Level Agreement ↗
- Granite — Canadian VoIP 911 English ↗
- Granite — Resources and customer portals ↗
Examples require adaptation to your topology. No live PBX or hardware testing is claimed.