Freeze the symptom before changing either route
Record the exact E.164 number, port batch, requested and confirmed date, former and gaining provider references, affected originating networks, time, calling number, destination reached and expected destination. Preserve one known-good and one failed call with carrier and PBX identifiers where authorized.
“Port complete” can describe an order milestone without proving that every originating network reaches the gaining path. A number visible in the new portal can also precede a correct PBX route. Keep those boundaries separate.
Prove the carrier ownership and routing boundary
Compare the current gaining-provider record, former-provider state and any country-specific range-holder or routing evidence available through the authorized carriers. Ask the gaining provider to trace the failed originating network and preserve its ingress or absence; do not infer the responsible carrier from caller display alone.
If some networks reach the new service while others reach the old one, preserve that split as routing evidence. Do not delete the old destination, reject all traffic or request a second port until the providers classify the first port state.
Follow one successful ingress through the new platform
For a call that reaches the gaining carrier, correlate provider call detail, ingress peer, SIP Call-ID, Request-URI or called number, PBX normalization, matched inbound route and final destination. A carrier record or accepted INVITE does not prove the queue, IVR, user or application answered.
If no INVITE reaches the intended edge, stay at the carrier and access boundary. Do not edit codecs, NAT or media settings for a signaling path that never arrived.
Check duplicate, partial and translated number inventories
Compare the ported number and any block, range, child account, location, platform assignment or old forwarding rule. Confirm that full and partial porting were not mixed, that the new platform owns the exact destination and that the old carrier did not leave an internal on-net route or forwarding treatment.
Keep E.164 storage, displayed national format, SIP Request-URI and PBX-normalized digits distinct. Correct normalization cannot repair an upstream route to the wrong carrier.
Protect emergency and specialist services during recovery
Do not use an ordinary inbound result to infer emergency callback, dispatchable location, fax, alarm, lift, paging or contact-center behavior. Maintain the approved parallel or alternative path and validate each regulated or specialist workflow with its owner and provider process.
If rollback is required, define which numbers, routes, addresses and notifications it changes. A rollback that restores ordinary calls but leaves an incorrect emergency record is not complete.
Close only after propagation and acceptance are evidenced
Retest from the agreed set of mobile, fixed, enterprise and international networks, then verify outbound identity and callback where applicable. Record the observation window, gaining-provider confirmation, PBX evidence and business-owner acceptance before requesting former-service decommissioning.
Archive protected traces with access limits and remove temporary captures. No port, route, provider, PBX or call was validated for this diagnostic.
Sources & applicability
Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.
- Pure IP enterprise SIP migration guide ↗
- Pure IP multi-country PSTN replacement guide ↗
- Pure IP customer and partner portals ↗
- Pure IP UK porting procedure (legacy, country-specific reference) ↗
Examples require adaptation to your topology. No live PBX or hardware testing is claimed.