SIP Trunking for Contact Centers: Think Global, Act Local

Posted by TENIOS BLOG on 24.11.2017
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Customer experience isn't just about live agents interacting with customers but also about the business processes and systems that support those agents. Even the most well-trained and experienced agent is limited by the applications used to interact with customers. Often, cumbersome and siloed legacy systems can be the cause of poor customer experiences. To benefit from the latest technology, more and more enterprises are opting for managed/hosted or on-demand contact center services. This is particularly the case for those enterprises that do not have the resources (financially or operationally) to purchase, implement, or maintain contact center technology and/or activities. The ease and flexibility of hosted and on-demand contact center services are among the key benefits that allow these enterprises to stay agile and enable the interactions that are so important to customer experience, and to do this via the required (digital) channels with local support.

Managing the contact center activities and required technology in-house, there are basically two contact center service models provided by external companies:

 Hosted, which is used to represent contact center services that are delivered via a dedicated, single tenant model.

 On-demand or cloud contact services, often referred to as SaaS, which represent those services that are provided from a shared, multitenant architecture.

While hosted and on-demand services are different models, many of the same market factors apply to both, and hosted is often seen as a stepping stone toward pure cloud contact center services. The multitenant model increases some of the benefits of hosted services, such as flexibility and lower cost, due to its shared architecture model.

Hosted and on-demand contact center services are often those systems that enable the interactions that are so important to customer experience. Contact center services can include any number of the following capabilities: ACD, IVR, skills-based routing, speech recognition, reporting and metrics tools, CTI and CRM capabilities and/or integration, workforce management, online recruiting and training platforms, and other capabilities that support contact centers and customer care processes. Often, much of the functionality is optional and/or provided through partnerships. These services are often the platform for supporting many channels, including phone, email, chat, and social media.

SIP trunking providers that primarily focus on interconnecting local public switched telephone networks from all over the world with centrally located contact center platforms using a global managed IP network (e.g., TENIoS etc.). These providers offer local telephone numbers (also known as DID numbers) from everywhere in the world, and deliver calls to these number over a single SIP trunk.


An important technology development for the contact center industry is SIP trunking (where SIP stands for session initiation protocol). SIP trunking has been available for a number of years, but in the past five years we have seen interest in the technology growing strongly, and we can now say that conversion to SIP is one of the major forces reshaping the call center. SIP covers all enterprise communication, not just contact centers, but for many companies the journey to an all-SIP environment starts with the call center.

IDC research shows that growth in SIP trunking services is evolving with the growing need for consolidation, flexibility, and efficiency — all benefits that help to lower operational costs. For globally operating enterprises and their contact centers in particular that need to localize or improve localized customer support, these benefits apply even more. The more countries served locally, the greater the synergy effect of the main benefits outlined below:

 Network consolidation. Enterprises are seeking ways to reduce telecom spend by leveraging their IP data networks for inter-site, intra-enterprise multimedia communication and consolidation of connectivity to service providers. SIP trunking offers the ability to consolidate the connection with the telephone network at a single site (or two sites for redundancy), even globally, instead of having an ISDN line at every single site. The cost and architectural advantages of this are obvious.

 Flexibility. One of the key benefits of SIP trunks over TDM-based services is flexibility in terms of capacity management and geographical reach. SIP trunk capacity can be managed per channel, and while services provisioned on ISDN lines are linked to a geography and location, location is not an issue with SIP trunks. Over a single SIP trunk, telephony services from different locations nationally and even internationally can be delivered. For example, you might have needs in two locations, with 20 concurrent calls in the U.S. and 20 concurrent calls in Germany. With TDM-based services, you would have needed 40 channels. With SIP trunking, you can allocate your capacity so that you need only 20 channels that you can use in the daytime in the U.S. and during the night in Germany.

 Efficiency. Instead of making the phone ever more complicated and expensive, SIP integrates the phone with the computer and enables contact centers to work more efficiently. Contact centers find it cost effective as it eliminates the need for more expensive contact center desk phones without sacrificing functionality.

 Other. When VoIP is coupled with SIP trunking the contact center can save costs by cutting back on toll-free numbers, as VoIP services can be used to enable click-to-call, which customers can initiate from their PCs or smartphones. In terms of enhancing the customer experience, SIP trunking also enables HD audio, which can be a real differentiator.

At the same time, however, there are some issues that can inhibit the growth of SIP trunking services:

 Complexity of implementation. Customers tend to underestimate the complexity of undergoing such a transformational change when implementing SIP trunking, particularly from a network architecture perspective. For some customers and SPs, this complexity is a key challenge when looking at implementing and purchasing SIP trunking services.

 Software and equipment versions. The existence of multiple vendors and multiple versions of each vendor's software is also hindering SIP trunking growth. Some customers may have several PBXs provided by different vendors at different times, making the whole license and software process for SIP trunking more time consuming.

 Equipment-related costs. The cost of upgrading the existing IP equipment (PBXs, session border controllers, etc.) and obtaining the necessary licenses and software to use them can account for a major part of a company's budget when considering implementing SIP trunking services. Replacing local equipment with a centralized contact center solution in a networked environment can, however, negate much of that cost.

Moving forward, IDC expects the benefits of using SIP trunking services to outweigh the challenges. IDC believes the growth in SIP trunking services will also be fueled by VoIP migration and equipment replacement cycles. A significant portion of the contact center networking infrastructure is reaching end of life, and this includes key communications equipment such as UC infrastructure and IP PBXs. Replacement cycles and upgrades will be key for SIP trunking deployments. The new equipment being installed is mainly IP enabled and supporting legacy TDM technology usually comes with a fee. An increasing number of vendors have made their equipment SIP enabled in recent years. The growth in the number of home-based agents is also driving use of SIP and IP-based softphone agents. Contact center agents can work from home while using the same platform as in-office agents. This can often simplify operations, training, and reporting by allowing the contact center data to flow through one system rather than in separate physical locations.

SIP trunking services are being offered under a variety of models with a few offering international SIP trunking services for both incoming and outgoing traffic. In most cases, these tend to be incumbent operators offering the services to large multinational organizations outside of their home market. However, not all providers offer SIP trunking services for call centers; in some cases the service is only available for enterprise use, but not for call centers. Local SIP trunking providers, on the other hand, tend to have a strong presence in their local markets but limit their service to national traffic and outgoing international services. In most cases the local providers concentrate on dedicated models inside their home market and act as an over-the-top provider, on top of other service providers' networks.

For contact centers and outsourcers it is important to bring calls to the local service numbers of their customers to the offshore contact center, with high quality and at a reasonable cost. Many contact centers operating internationally have agreements with multiple voice carriers for the international reach of their telephone support service. For this, they are usually charged per minute fees for the international transit of inbound calls, and this can be a substantial amount in the case of toll-free numbers. In addition, the more countries involved, the higher the administrative burdens of vendor management for contact centers. Although an increasing number of telco operators provide their customers with SIP trunking services, global coverage is often too limited (global carriers' networks reach up to a maximum of 30 countries on average), and often their offers are limited to toll-free numbers. As TENIOS uses its private data network instead of international PSTN transit networks, no per minute fees are charged for the international transport of the calls as is the case with most telco operators. Instead, customers pay for the reserved call capacity on global IP backbone, which can be shared by all 55 countries the company provides services from.


The need to enhance and innovate customer experience is growing. Customer service and contact center solutions have been trying to meet the needs of the masses, and adapting simply to the situation as it looks at the moment of contact. However, influences from the consumer market are leading to changes in how end users prefer to interact and how they expect customer services to be provided. Customers now expect cross-channel knowledge of earlier interactions, and consistent support irrespective of when and how they communicate or from where they chose to do so. This means that contact centers must be much more innovative and agile than ever before to meet these growing expectations. In addition, contact center managers understand the need to deploy contact center technology and processes globally, but that take into account customers' local differences in communication habits or needs. Localization of service support is key, and will continue to be so.

Contact center managers are questioning how they can bring their existing installation up to modern standards and how to incorporate modern capabilities such as social media analytics and social engagement while keeping the lights on. For enterprises with contact centers it is also increasingly important to have capabilities such as flexibility and scalability to address seasonal changes, consolidation of systems for international consolidation of customer support activities, and international expansion of customer service operations. As for an increasing number of enterprises with contact centers, hosted and/or on-demand contact center services are the answer. For some of these enterprises existing (premises-based) infrastructure is at the end of its life cycle; others are successful newcomers that are expanding quickly and leapfrogging to an end-to-end on-demand model — outsourcing technology and perhaps also contact center activities — rather than trying to build an advanced infrastructure on premises. All of these drivers indicate that contact center technology platforms are clearly moving toward as-a-service models in cloud or hosted deployments.

An important technology development for the IP telecommunications industry and its customers is SIP trunking. The contact center is a natural place to test out SIP trunks because it may be easier to centralize a subset of the communications infrastructure than it is to try and move the whole system over. SIP trunking has proven that it can enable or improve consolidation, flexibility, and efficiency — all benefits that help to lower operational costs. For globally operating enterprises and their contact centers in particular, SIP trunking is an important transport technology service to enable or improve localized customer support. Since most contact centers are inherently B2C in nature, this represents a large chunk of the enterprise's voice traffic going to and from the public network. For contact centers with a major international reach, global SIP trunking services are an efficient and cost-effective solution to provide local, geographical, and toll-free support numbers from all countries required. Using a private data network for the international transport of calls is a key requirement for carrier-grade voice quality and an important cost saver as it avoids per minute fees for international transit. Such a service offers the opportunity to consolidate contact center infrastructure, localize customer experience, and reduce telecommunication costs.

Topics: call-center, ip-access, sip-trunk, sip-trunking