Identify Smart SIP, SIP Advanced and the governing agreement
One NZ presents Smart SIP for smaller deployments and SIP Advanced for more advanced or multi-site requirements. The family page uses fewer than or more than fifteen simultaneous calls as a selector, but the current product records overlap: Smart SIP permits four to fifteen Calling Channels and SIP Advanced publishes a ten-channel minimum. Ten through fifteen channels therefore do not identify the ordered product by themselves.
Record the exact legal service name, service description, pricing schedule, site and order. SIP Advanced was formerly called SIP, while Smart SIP has its own service description, access choices, portal controls, restrictions and support targets. Do not transfer a feature, limit, term or price between them.
Documented service facts
Reviewed 2026-10-27. Compare SIP trunk services →
SIP authentication
Not verifiedPublic records do not establish one universal credential, certificate or source-address model for both services. The selected implementation specification governs.
SIP registration
Not verifiedA universal REGISTER requirement, registrar, proxy, expiry or Contact policy was not established for every One NZ SIP design.
DDIs and inbound delivery
DocumentedSmart SIP documents DDIs, local-number porting and per-DDI emergency locations. Allocation, activation, delivered number, PBX match and completed calls remain unverified.
Diversity and alternate access
DocumentedSIP Advanced distinguishes Multi-Site and Dual Circuit options; Smart SIP documents 4G as possible primary or failover Access. Order, path diversity, trigger, call result and restoration remain unverified.
Access and demarcation
DocumentedBoth services require site Access and supplied One NZ routing equipment; Advanced and Smart document different access and presentation details. Site feasibility and the selected design remain unverified.
Signaling and media
Not verifiedPublic records do not establish universal signaling targets, transport, codecs, DTMF or media ranges for every ordered service. Implementation evidence and observed packets govern.
Fax and non-voice use
Not verifiedThe reviewed current records do not establish universal fax, T.38, modem, EFTPOS or alarm compatibility. Exact service, device and end-to-end results govern.
Transport and media protection
Not verifiedSecure product language is not a published universal TLS, certificate or SRTP profile. The ordered implementation and observations govern.
Trunks and Calling Channels
DocumentedSmart SIP documents four to fifteen Calling Channels; SIP Advanced publishes a ten-channel minimum and a scalable pool. The overlapping range does not identify the product or prove account capacity.
111 and location evidence
DocumentedCurrent service descriptions say Calling Channels should not be the primary 111 or alarm path; Smart SIP requires current DDI locations and warns about power or transmission failure. Account readiness remains unverified.
Term, price and availability
DocumentedProduct pages publish selected term and Smart SIP price information, but the governing pricing schedule, site feasibility, installation and selected options determine one order. No universal current price or availability is inferred.
PBX, support and service levels
DocumentedBoth services require compatible customer PBX evidence. Published support targets and the SIP Advanced 99.7% dual-diversity target retain their exact conditions and boundaries.
SMS and MMS
Not verifiedThe reviewed One NZ SIP records do not establish SMS or MMS on trunk DDIs.
Bind each site to its access, equipment and demarcation
SIP Advanced requires One NZ Access at each site, and the current product page says One NZ Metro Access is required. Its service description places the demarcation at the supplied One NZ router, with access terminating at the site ONT and the trunk presented from that router as SIP over Ethernet or through an optional ISDN emulator.
Smart SIP instead documents one primary Access and one trunk per site, with Fibre, HSNS or 4G Cellular among the possible access types. Its supplied Edge Router is the demarcation point when no emulator is required. Preserve the exact order, access circuit, ONT, router or emulator, interface, addressing, routing and customer-side PBX boundary.
Treat PBX approval and vendor lab access as bounded evidence
Both product pages require a compatible PBX. SIP Advanced advertises a lab environment for vendors to certify system compatibility, but that does not establish that one customer model, software release, SBC, topology or loaded configuration was certified or accepted. Smart SIP makes the customer responsible for compatibility, downstream wiring, interconnection, programming and support on the customer side of the point of connection.
The public material reviewed here does not publish one universal registrar, source-trust model, authentication method, signaling target, transport, codec set, DTMF mode, media range or encryption profile. Obtain the current order and implementation specification and compare them with generated and loaded PBX state.
Keep trunks, Calling Channels, DDIs and portal records separate
A SIP trunk is the per-site virtual connection; Calling Channels form the pool of simultaneous PSTN calls carried over it. Smart SIP documents four to fifteen channels, with portal changes within those bounds. SIP Advanced documents a scalable channel pool and separately publishes a ten-channel minimum. Ordered channels, portal display, active dialogs, call attempts, bandwidth and PBX resources remain different measurements.
Smart SIP documents included DDIs, local-number porting and a portal location value for each DDI for emergency-calling purposes. Number reservation, port authorization, provider activation, DDI location, inbound attempt, PBX receipt, route match and completed call remain separate checkpoints.
Distinguish multi-site diversity, dual circuits and 4G failover
SIP Advanced lists Multi-Site diversity and Dual Circuit as different add-ons. Multi-Site can forward calls to another site after a service outage; Dual Circuit provides more than one physical circuit to one site and should use diverse paths. The 99.7% target in the current service description applies where dual Diversity or higher is taken and is measured at the One NZ service-edge boundary over a rolling three-month period.
Smart SIP documents 4G Cellular as a possible primary or failover Access. An option, second link, portal state or target is not proof that the ordered design includes it, paths are physically diverse, calls moved, established calls survived, media worked or primary routing was restored.
Make emergency, availability and commercial claims service-specific
Both current service descriptions say Calling Channels should not be the primary service for 111 or alarm monitoring. Smart SIP also states that emergency calling may not work during power failure or transmission errors and requires customers to keep each DDI location current in the portal. The general One NZ 111 page explains emergency calling but does not prove one SIP site address, callback, power or alternate path.
Preserve the service-specific support and availability definitions, exclusions, measurement boundary and selected options from the governing agreement. Obtain the current pricing schedule and feasibility result rather than inferring price, availability or compatibility from a public selector. Validate emergency readiness through an approved non-live process; do not place an uncoordinated 111 call.
Sources & applicability
Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.
- One NZ — SIP for business ↗
- One NZ — SIP Advanced ↗
- One NZ — SIP Advanced Service Description ↗
- One NZ — Smart SIP ↗
- One NZ — Smart SIP Service Description ↗
- One NZ — Terms, conditions and service descriptions ↗
- One NZ — Metro Access Service Description ↗
- One NZ — Master Services Agreement ↗
- One NZ — About Emergency Services on 111 ↗
Examples require adaptation to your topology. No live PBX or hardware testing is claimed.