SIP trunking isn’t quite as “sexy” of a topic as videoconferencing or UCaaS
, but this decades-old technology it is seeing renewed importance as a “fundamental backbone” for bring your own carrier (BYOC) voice connectivity options for services like Zoom and Microsoft Teams, shared Diane Myers, research analyst of Omdia, during a recent No Jitter briefing on her recently published SIP trunking service provider scorecard for North America
In other words, SIP trunking is starting to look a little bit more interesting than connectivity alone, and the providers that stand out are the ones that are positioning themselves by saying, “‘Look, Microsoft and Zoom are going to get the applications, but we can do a lot of interesting things underneath the hood,’” she added.
This Omdia SIP trunking scorecard, based on 2019 data, takes factors such as financial strength, market share momentum, service development, and support options into account, Myers said. Based on these criteria, below are the 10 leading SIP trunking providers in North America, with a summary overview:
- CenturyLink – As the largest SIP trunking provider in North America, CenturyLink has strong suits in global enterprises and multinationals, as well as in Cisco and Microsoft shops. Its premiere offering is Voice Complete, which supports a wide variety of PBXs, local and long-distance calling with local numbers and emergency services, business continuity and disaster recovery, and an array of enhanced calling services. In addition, CenturyLink supports hybrid deployments with Voice Complete and IQ SIP Trunk, an integrated service for SMBs, along with hosted cloud UC and contact center options. Building on its SIP trunking services, CenturyLink also offers managed and private cloud UC and contact center services, with direct routing support for Microsoft Teams for Voice Complete and IQ SIP being one focus. In addition, it is working to improve its delivery and customer experience, with an eye on expediting installation and simplifying the number portability process.
- Verizon – which ended 2019 with the second-largest installed base of SIP trunks, continues to roll out enhanced capabilities for IP connectivity. Sold directly and indirectly to customers, Verizon’s SIP trunking service is available in up to 40 countries, 27 of which include PSTN replacement. Over the years Verizon has made SIP trunking services easier to order, consume, and manage, offering mobility integration, Secure Cloud Interconnect and FiOS access; SIP trunking with SD-WAN; and a wide set of certified access and IP PBX equipment options, for example. Verizon was one of the first providers to offer centralized, multisite, multi-country designs, allowing global customers to maximize their CPE and network configurations. “Old-world [telephone companies] like AT&T, CenturyLink, and Verizon very much still lead a lot of the activity [in SIP trunking,” Myers said.
- Inteliquent –Inteliquent (formerly Voyant) has the third-largest installed base of retail customers and the strongest market momentum compared to other providers on this list. Inteliquent has expanded SIP trunking options to include interoperability-tested direct routing for Microsoft Teams, e-911 integration, toll-free calling, SMS/MMS, and message-enabled phone numbers. A differentiation Inteliquent has from other over-the-top (OTT) providers is that it owns the voice network, allowing connectivity via public Internet, MPLS circuits, VPN tunnels, or dedicated connections into its own network. In addition, Inteliquent offers SIP trunking features as an API, to best suit individual customer needs.
- Twilio – Previously ranked at number two, Twilio dropped on the list because other companies had “better [market] momentum and its growth in SIP trunking wasn’t as strong,” Myers said. Twilio differentiates itself as an API provider, enabling the ability to provision and manage SIP trunks in just a few minutes via its Elastic SIP Trunking product, as well as through its analytics capabilities, Voice Insights for Elastic SIP Trunking and Interface. Elastic SIP Trunking is available from the Twilio cloud and is available on a metered price-per-minute basis — no per-trunk or per-port charges. Twilio supports more than 80 infrastructure variants and has interoperability guides for six IP PBXs and nine enterprise session border controllers. “Twilio can provide a connection pipe, APIs, and a lot of other interesting [capabilities] beyond connectivity,” Myers said.
- AT&T – AT&T remains a top SIP trunking provider through the growth of its installed base, market momentum, financial stability, and nationwide presence. Its size and reach are competitive advantages. AT&T offers SIP trunking as part of IP Flexible Reach, a converged service that runs over AT&T’s Internet and VPN services to support a range of bandwidth requirements. For voice trunking, AT&T supports non-SIP PBXs through either an AT&T-managed or a client-managed router. AT&T also offers virtual telephone numbers (VTNs), allowing customers to assign telephone numbers not physically located within a specific calling area.
- Bandwidth – SIP trunking is one of Bandwidth’s core services. Although the company is the ninth-largest provider, its financial score and service development place it at number six in the 2020 scorecard. Bandwidth primarily sells SIP trunks to businesses with on-premises solutions but has shifted focus providers looking for BYOC relationships for UCaaS and CCaaS customers. Key capabilities of this offering include e911 integration, disaster recovery and IP failover control, and API-enabled access to calling and billing records.
- IntelePeer – SIP trunking isn’t currently a core focus for IntelePeer, which has turned its attention to its CPaaS portfolio via its Atmosphere Communications Platform. Still, the size of its installed base and its continued growth momentum in SIP trunking. Atmosphere SIP customers have access to CPaaS platform APIs, including voice, SMS, workflow automation, pre-built and customizable applications, as well as predictive analytics.
- Fusion – Via its FusionSIP offering, Fusion offers SIP trunking to more than 40 different PBXs. It’s available under three service packages, priced based on the number of concurrent call paths, local and long-distance plans, and capacity allocation across customer locations. Customers can provide their own bandwidth or run it over dedicated Internet access from Fusion. The company uses integrated access devices for PBXs that don’t support SIP. As at IntelePeer, SIP trunking and other fundamental services are what “pays the bills” for Fusion, Myers said.
- Voxbone – This is Voxbone’s first time on this list, making the cut as the 10th largest provider in North America with a boost from strong momentum in 2019. Via its SIP trunking service, Voxbone offers national calling capabilities across 65 countries, native integration for SIP trunks for a range of PBXs, and BYOC connectivity for Microsoft Teams, Zoom Phone, and Genesys Cloud. Voxbone continues to invest in its core platform and tools to simplify number porting and to enable emergency services.
- Windstream – This provider has gained a strong position in business VoIP through hosted, managed PBX, and connectivity services; for SIP, it offers Dynamic IP SIP Trunking. Windstream has a weaker financial score and slower momentum than other providers, which drops it down the list. Windstream offers enhanced service capabilities, such as call path pooling, expanded off-net coverage, and disaster recovery.
In SIP trunking, the choice often comes down to the fundamentals of scaling, voice quality, and pricing, Myers said. “That’s where some of the big companies have a long history, and a lot of installed base customers have traditionally gotten voice connectivity from them,” she added. “But it does begin to shift” when looking beyond connectivity alone.