Freeze the order, site and failed attempt
Record UTC and local time, exact service and agreement, order, site, access circuit, provider handoff, router or SBC, PBX and software, ordered channels and DDIs, direction, calling and called numbers, first response, answer and audio result. Redact secrets while preserving field names and retrieval time.
Classify the first unexpected boundary: order, feasibility, access, demarcation, PBX, capacity, DDI, request, response, dialog, media, reroute or restoration. Do not substitute generic product-page language or another customer configuration for the current implementation evidence.
Prove access and handoff before PBX changes
Verify the exact circuit, addressing, routing, router or SBC, firewall and customer/provider boundary named in the order. Establish state on both sides of the handoff before changing NAT, SIP ALG, credentials, identification rules or PBX objects.
A link light, internet session, DNS answer or reachable address does not prove that the trunk or identity is accepted. Preserve the first SIP request and response at an authorised observation point and keep provider-side and customer-side responsibilities explicit.
Map the implementation pack to loaded PBX state
Retrieve the current 2degrees implementation specification and map its registrar or source-trust model, signaling targets, transport, ports, identities, number format, codecs, DTMF and media ranges to generated configuration and loaded PBX objects. The public page does not define a universal profile.
Correlate request, response, SDP and packet evidence by the same Call-ID. After answer, prove both media directions, selected codec, decoding and audible result separately. Do not infer encryption or call quality from the words internet, reliable or high quality.
Trace channels and DDIs independently
Compare the ordered channel quantity with provider records, active dialogs and the exact rejection. Keep trunks, channels, marketed phone lines, simultaneous calls, bandwidth and PBX resources as different measurements.
For inbound failure, preserve number allocation or port state, provider attempt, delivered called-number value, PBX receipt and route match. For outbound failure, preserve selected trunk, source identity, Request-URI, response sequence and restriction. A number record or accepted SIP transaction is not proof of a completed call.
Prove the exact reroute or continuity design
Confirm whether the order includes provider rerouting, a second data path, PBX redirection to mobile, or another design. Record the trigger, owner, source and target, provider action, PBX route, new-call result, established-call behavior, media and restoration.
Do not treat the product page description as proof that failover is automatic or included. A configured mobile destination, alternate circuit or successful control-plane change does not prove call completion, feature preservation, physical diversity or recovery.
Retest one correction and close with bounded evidence
Apply one authorised correction and repeat the affected ordinary call plus an unaffected control. Preserve access and handoff state, loaded PBX configuration, SIP exchange, DDI match, channel count, answer, both media directions and hangup. Retain rollback criteria until the approved cutover is complete.
Attach the governing order, implementation evidence, provider records and case observations. Validate power, alternate calling and emergency-location readiness through an approved non-live process; do not use 111 as an uncoordinated diagnostic. No 2degrees service, call, media path, reroute or emergency result was tested for this diagnostic.
Sources & applicability
Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.
- 2degrees Business — SIP Trunks ↗
- 2degrees — Terms and conditions index ↗
- 2degrees — What happens in a power cut ↗
- 2degrees — Vulnerable consumers and calling 111 during a power outage ↗
- 2degrees — Privacy policy ↗
Examples require adaptation to your topology. No live PBX or hardware testing is claimed.