Freeze the contract, application and failed attempt
Record UTC and local time, customer audience, legal service name, agreement version, application, site, Evolve IP VPN, managed or customer-router model, service-delivery point, PBX and software, selected features, active channels, numbers, 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: contract, order, access, service-delivery point, router, PBX, number, capacity, request, response, dialog, media, diversion or restoration. Do not substitute CSP-Connect, a wholesale description, an older factsheet or another customer's configuration.
Prove access and the documented handoff first
Compare the current application and OM.37683 with the delivered Evolve IP VPN, MRS or customer-managed router, NTU, interfaces, addressing, routes and quality policy. Establish state on both sides of the exact service-delivery point before changing firewall, NAT, SIP ALG, credentials or PBX objects.
A reachable Optus address, active access circuit or link light does not prove that the selected trunk, source, number or identity is accepted. Preserve the first request and response at an authorized observation point and keep customer, access and Optus ownership explicit.
Trace numbers, channels and fax independently
For inbound failure, preserve number allocation or port state, provider attempt, delivered Request-URI and called-number headers, PBX receipt and route match. For outbound failure, preserve selected trunk, source identity, Request-URI, Call-ID, response sequence and restriction. Number presence, port completion and an accepted SIP transaction are not proof of a completed call.
Compare application-specified Active Channels with current dialogs and rejected attempts. When fax is affected, record the selected ordinary audio or T.38 path, negotiation, packet directions and completed-page result independently; a T.38 channel in the application is not proof of negotiation or delivery.
Use the current technical description for signaling and media
Retrieve the current OM.37683 and map its registrar or source-trust model, signaling targets, transport, ports, identity, number format, codecs, DTMF and media ranges to generated configuration and loaded PBX state. Do not treat values from the 2017 factsheet or older technical paper as current account settings.
Preserve request, response, SDP and packet evidence for the same call. After answer, prove both media directions, selected codec, decoding and audible result separately. An Ethernet handoff or packet-based service description is not evidence of one call's media path or quality.
Prove the selected continuity feature and restoration
Confirm whether the application specifies Emergency Diversion, Dual Voice Trunk or Dual Exchange Homing. For diversion, preserve authorized requester, current destination, password handling, Optus acceptance, affected numbers, provider route, destination result and cessation. For a dual service, record each access path, service, voice-switch relationship, PBX selection and test result.
A control request, second link or alternate trunk is not proof of completed calls or feature preservation. Optus states that all features are not guaranteed during diversion. Keep established-call behavior separate from new-call routing and verify restoration to the intended primary path.
Retest one correction and close with bounded evidence
Apply one authorized correction and repeat the affected ordinary call plus an unaffected control. Preserve access and handoff state, loaded PBX configuration, SIP exchange, route match, channel count, answer, both media directions and hangup. For porting, fax, diversion or dual-service work, keep rollback criteria and former paths until approved cutover is complete.
Attach the current application, OM.37683 excerpt and provider case observations. Confirm emergency address, identity, callback, routing, power and alternate calling through an approved non-live process; do not use an emergency number as an uncoordinated diagnostic. No Evolve Voice service, call, fax, diversion, dual trunk, media 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.
- Optus Wholesale — Evolve Voice SIP trunking ↗
- Optus — Evolve Service Description, 1 November 2025 ↗
- Optus Business — Standard Form of Agreement, Evolve ↗
- Optus Business — Standard Form of Agreement ↗
- Optus — Evolve Voice factsheet (historical 2017 context) ↗
- Optus — SIP Trunking technical paper (historical context) ↗
Examples require adaptation to your topology. No live PBX or hardware testing is claimed.