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The Future of SIP Trunking

Engineers, CTOs, and product leaders have spent the last decade debating the commercial feasibility of SIP Trunking. In this blog post, we explain why we believe the future of SIP Trunking is bright.
March 12, 2021

The Future of SIP Trunking

When SIP Trunking adoption first began to accelerate, many hailed it as the future of voice communication. The technology has many benefits over analog telephony, as we’ve discussed previously, and is poised to become the dominant method for voice calls globally, with providers in numerous countries shutting down legacy connections and essentially forcing enterprise users to switch to SIP. Still, many voice experts I have encountered, such as engineers, CTOs and product leaders, have spent the last decade debating the longevity of VoIP services and SIP Trunking in terms of commercial feasibility and revenue growth. How can this be?

The answer lies with the very thing that has improved SIP performance and helped it go mainstream – the introduction of fast, reliable internet connectivity. Voice and unified communications have seen several innovations that have transformed the space, and many new players have emerged on the scene, from early innovators like Skype to newly prevalent platforms like Zoom. As enterprises adopt cloud telephony, internal calls no longer traverse the PSTN, which begs the question: with these new cloud-based phone systems, do enterprises really need the PSTN anymore? Is SIP Trunking already becoming obsolete, or does it still have a role to play?

The Abundance of Cloud Telephony Players and Features

Cloud phone systems like Microsoft Teams are ubiquitous and have changed the way we work and communicate. The Covid-19 pandemic has accelerated adoption even further – most of us have used Teams or Zoom for either personal or work reasons over the last year. These platforms bring people together to collaborate in a variety of ways, including chat, video, voice, and even integration with other cloud-based services such as Office 365. For larger enterprises, these platforms offer additional value in the form of cost savings and simplicity. In addition, the adoption of cloud telephony can greatly decrease capex by removing the need for a PBX at every site, and free up IT resources previously tasked with managing a decentralized solution.

The Role of SIP

With cloud phone providers exploding in popularity, one might assume that SIP Trunking is poised to go into decline. Research and Markets predicts that the SIP market is projected to reach US$ 30.22 billion by 2027. This growth comes as many enterprises are still transitioning away from TDM, with SIP offering attractive reductions in price and greater flexibility. SIP is a technology that can and should coexist with cloud telephony for one simple reason: enterprises still need to connect to the PSTN.

Platforms such as Microsoft Teams or Cisco WebEx offer powerful new communication and collaboration tools, but on their own, they cannot encompass every possible voice calling scenario. Employees still need to make and receive external calls. Salespeople need to contact external prospects. Service representatives need to communicate with customers. Procurement teams need to connect with vendors. All end users must be able to contact local emergency services. Perhaps most importantly, contacts from outside the enterprise need a number to call to ask questions, request service, make an order, and so on. All of these rely on the PSTN.

Fortunately, cloud phone providers and VoIP telecommunications providers can work together to deliver the best of both worlds to enterprises: the rich feature-set of cloud telephony with inbound and outbound calling to the PSTN over a SIP trunk.

Choosing the Right SIP Partner

In order to reap the combined benefits of cloud telephony and SIP, enterprises need a voice service provider that has a deep SIP footprint to cover all corporate sites and that can work with their cloud phone provider of choice to ensure call quality. Seamless integration is vitally important, and the ideal partner should offer pre-established, fully redundant direct SIP Trunking routes as well as access to knowledgeable SIP engineering experts to help architect the solution.

As a globe-spanning Tier 1 enterprise telecom MSP, GTT is perfectly situated to be your SIP Trunking partner. Our voice solution is built across GTT’s global IP backbone, delivering high call quality and reliability, with pre-established connections to two leading cloud phone system providers: Microsoft Teams and Cisco Webex Calling. GTT can ensure high call quality and seamless integration between your cloud phone system and your voice solution.

About GTT

GTT is a managed network and security services provider to global organizations. We design and deliver solutions that leverage advanced cloud, networking, and security technologies. We complement our solutions with a suite of professional services and exceptional sales and support teams in local markets around the world. We serve thousands of national and multinational companies with a portfolio that includes SD-WAN, security, Internet, voice, and other connectivity options. Our services are uniquely enabled by our top-ranked, global, Tier 1 IP backbone, which spans more than 260 cities on six continents. The company culture is built on a customer-first service experience reinforced by our commitment to operational excellence and continuous improvement in our business, environmental, social and governance practices. For more information, visit


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