SITEL Voice Architecture www.sitel.com SIP Voice Architecture: What is it? And how contact center operators can save money using it. By: Kevin Weier, Director, Global Voice Infrastructure and Architecture, Sitel Operating Corporation.
Abstract Few technology advancements have had a greater impact on the corporate enterprise than the development of Internet Protocol (IP). Few technology advancements have had a greater impact on the corporate enterprise than the development of Internet Protocol (IP). Indeed, the birth of the Internet and the enterprise networks and business applications it supports can be linked directly to the evolution of IP. Today IP is playing a fundamental role in the development of another important new technology, a signaling protocol called Session Initiation Protocol, or SIP. SIP delivers the functionality and efficiency enterprises need to roll-out advanced, real time voice and video over IP applications. With SIP, Sitel and other companies that rely heavily on voice communications will be able to substantially reduce their communication costs while offering end users a wide range of exciting new services. Page 02
Legacy PBX Platform To fully appreciate SIP, one must compare it to its predecessor technologies, beginning with the Private Branch Exchange (PBX). To fully appreciate SIP, one must compare it to its predecessor technologies, beginning with the Private Branch Exchange (PBX). A PBX is a telephone system located on an enterprise site that 1) switches calls between a company s internal users on local lines while 2) also providing shared access to a finite number of external phone lines. The PBX saves the company money because it doesn t have to provide each user with a dedicated phone line. Early PBX designs, which used Time Division Multiplexing (TDM) to process and deliver voice communications, were complex and costly to operate. For example, TDM platforms required a dedicated internal wiring network, one entirely separate from the local area network (LAN) wiring that interconnects (and delivers Internet access to) the company s computer network. For outside calls, the PBX interfaced with the external Public Switched Telephone Network (PSTN) basically every interconnected voice-oriented public telephone network in the world via expensive, hardware intensive gateways. Each enterprise site, therefore, required a PBX to connect with a carrier s long-distance network. And each PBX had to be outfitted with gateway equipment -- equipment that consumed a great deal of electricity, required a great deal of space, and needed a dedicated organization to maintain it. Legacy PBX Platform Therefore, legacy PBX equipment proved to be especially costly for companies like Sitel, which maintains a global network of hundreds of contact centers. Each contact center required its own PBX and gateway equipment. And calls could only be distributed within each location. If a call had to be transferred to another call center, it had to be sent back across the PSTN at costly rates. Page 03
Legacy PBX Platform... it s easy to see why Sitel and others began moving to IP-based telephony platforms in the 1990s. Proprietary standards Legacy PBX systems were also designed via proprietary standards. That increased costs further because it was difficult to 1) customize the PBX to meet specific business requirements and 2) integrate business applications like call recording or IVR. An application integration, for example, had to conform to each vendor s design specifications, often required multiple servers and still delivered only limited functionality. Each PBX also required a dedicated (and costly) instance of each business application. For an enterprise with multiple locations, the business application costs alone were substantial. Add the cost of hardware, leased space, electric power, and support services and it s easy to see why Sitel and others began moving to IP-based telephony platforms in the 1990s. Page 04
The IP Telephony Platform By combining the two networks, an enterprise no longer needed inbuilding voice wiring and a service organization to maintain it. As IP-based applications became more commonplace, PBX designs evolved from a closed system based on proprietary standards to an IP-based platform design based on open standards. That made business applications easier to integrate and allowed companies to combine their once-separate voice and data networks. By combining the two networks, an enterprise no longer needed in-building voice wiring and a service organization to maintain it. Voice calls could now be sent across the same internal network that supported the company s data communications. That allowed companies to move external inter-company (city to city or country to country) calling from the costly PSTN to its private (and much cheaper) wide area network (WAN). For contact center outsourcers like Sitel, this meant one centralized PBX could serve multiple call centers, regardless of their location. As long as the center was part of the WAN, the PBX could support it. Trunk lines (multiple phone lines that terminate at the PBX) could be centralized and aggregated at a single location, thereby providing substantial economies of scale and delivering more flexible call routing. However, despite these advantages, there were still limitations. A PBX, for example, can only support 3,000 to 4,000 contact center agents. Business application instances were still required for each PBX and a substantial amount of gateway hardware was still needed to interface with the PSTN. As a result, the costs associated with the IP PBX design were still relatively high especially for a contact center enterprise with hundreds of locations. PSTN Gateways IP PBX Still, it was a major improvement. Many corporations, including Sitel, employ a global voice architecture largely based on IP telephony. Large, centralized PBX systems called T-Hubs serve enterprise sites in multiple regions. In some cases, the trunk lines and PSTN gateways are centralized at the T-Hub and voice calls are sent across the WAN to international call centers. In other cases, the trunk lines and PSTN gateways are distributed to one site, while the calls are controlled by the centralized PBX at another. Page 05
SIP Architecture Sitel and many others are now looking to upgrade to SIP, a new signaling protocol... However, Sitel and many others are now looking to upgrade to SIP, a new signaling protocol widely used to control communication sessions such as voice and video over an IP network. SIP promises to resolve key PBX-related design issues, including: Excessive gateway hardware needed to interface with the PSTN; Redundant business applications one for each PBX; And the distributed PSTN circuits required for each PBX. Under a SIP-enabled design, the PBX maintains the unit s core call processing application, but the connection and call routing functions are moved to a SIP Session Management (SM) platform. By placing these functions on the SM platform, multiple PBX locations can connect to and share the same business applications. In fact, with SIP s Session Management platform, the next step becomes embedding communications right into the business processes themselves. This will improve processes by removing whole intermediary manual steps and making the business more agile and responsive to customer needs. DATA CENTRES Avaya Aura TM Communication Manager Applications Server SIP Trunking Contact Centre Session Manager Session Manager Avaya Contact Centre Contact Centre Avaya Nortel Siemans Page 06
SIP Architecture... because the SM is also the routing engine, calls can be easily routed between enterprise sites. This alone represents substantial cost savings because instead of paying for and installing redundant instances of the same business application on each PBX, an enterprise like Sitel can place a single application instance on the SM platform and connect multiple PBXs to it. And because the SM is also the routing engine, calls can be easily routed between enterprise sites. Further, with carriers like AT&T and Verizon beginning to adopt SIP, there has been a migration away from the old PSTN T-1 trunk lines to advanced IP SIP-enabled trunk lines, with the SIP trunks carrying the voice communication between the SM platform and the public network. Because it is an IP trunk, it can also carry Internet traffic and connect directly to a corporate IP network -- without the costly gateway equipment. As a result, the traditional (and expensive) data racks filled with gateway equipment can now be replaced by a server based Session Border Controller (SBC). Page 07
Session Border Controller (SBC) The SBC serves as a voice firewall that protects corporate or carrier networks from security breaches via the Internet... The SBC serves as a voice firewall that protects corporate or carrier networks from security breaches via the Internet or other outside facing traffic. There are two ways the SBC accomplishes this. The first is by standard encryption, either at the signaling or media level. Though it s part of the SBC design, the use of signaling encryption is optional and normally accomplished via Transport Layer Security, or TLS. On the media level encryption is accomplished via Secure Real Time Transport Protocol, or SRTP. The SBC can also enhance security by providing Network Address Translation, or NAT, which involves modifying an IP Address while it s being routed through the network. The most common application involves providing an IP Address translation to external or Internet facing devices, while all internal or protected devices sit hidden behind a NAT IP address. The SBC essentially serves, therefore, as a filter that prevents an internal IP address from accessing or connecting to certain external sites. ENCRYPTION NETWORK ADDRESS TRANSLATION DISASTER RECOVERY FEATURES... SBC IP Compatible Network Session Border Controller Last but certainly not least, an SBC can also serve as a major contributor to a company s disaster recovery strategy by rerouting calls and delivering SIP signaling generalization, SIP call recording and PBX capabilities. Page 08
SIP Savings... faster/more flexible service delivery is especially critical to meeting changing customer needs. In a fully evolved SIP architecture all of the enterprise s trunks are centralized and calls can be distributed to any PBX. Business applications placed on the SM platform can be shared across PBXs. And because there is a common signaling protocol, integrating these applications is now a relatively simple process. Though the return on investment (ROI) associated with a SIP migration is usually substantial, it can be difficult to calculate because of varying carrier and equipment vendor costs. In general, the savings fall into three categories: Converging the IP and telephony networks Most of the savings here are realized via a substantial reduction in carrier charges; more efficient use of bandwidth capacity; a single internal organization serving both voice and data; and faster more flexible service delivery options. For a contact center operator like Sitel, faster/more flexible service delivery is especially critical to meeting changing customer needs. This is why the contact center industry as a whole is migrating away from legacy TDM services to SIP. Business Process Business Communications Applications BUILDING BUSINESS VALUE Any Network Business Applications Intelligent Communications embedded into the fabric of business Business Process Any Network EMBEDDED Business Agility Competitive Differentiation Process Inprovement Customer Loyalty Employee Retention PBX Business Applications Network CONVERGED Cost Reduction Operational Efficiency Distributed Applications Security Reliability TRADITIONAL Page 09
SIP Savings... the ability to call any location without incurring a carrier charge represents a substantial cost savings in and of itself. Replacing traditional TDM with IP based equipment Replacing traditional TDM with IP based equipment reduces the equipment footprint and the subsequent cost of office space and maintenance. In most cases, migrating to a SIP-architecture can reduce footprint requirements by 60 percent or more, depending on the vendors involved. That, in turn, significantly reduces the monthly lease, HVAC requirements and electricity consumption. For many enterprises, this category is the biggest money saver. Leveraging the internal WAN Sending and receiving interoffice calls globally via the company s internal WAN infrastructure called tail end hop off reduces carrier charges and overall telecommunication costs. For a global enterprise like Sitel, the ability to call any location without incurring a carrier charge represents a substantial cost savings in and of itself. Add SIP s ability to support video, chat, presence and unified messaging and it s easy to see how moving to an SIP architecture not only lowers overall communication costs but also helps an enterprise deliver new and/or greatly improved communication services. Page 10
Summary & Conclusion SIP will play a fundamental role in forever changing the way the contact center industry operates. The transition to SIP architecture is already well under way. With so many carriers and vendors now supporting it as their primary protocol, most analysts believe SIP will soon be the industry standard. Contact center outsourcers like Sitel are already seeing the shift. For example, call center software providers are now delivering cloud-based global IP Telephony services, 24/7. A fully evolved SIP architecture will soon allow service providers like Sitel to offer customers a full and growing menu of communication applications, including unified voice, chat, texting, and video communications regardless of whether the agent is located in a traditional contact center, or working at-home. That means once the initial investments in SIP infrastructure are complete, the promise of long term costs savings will be realized by both service providers and their customers. Suffice to say SIP will play a fundamental role in forever changing the way the contact center industry operates. Page 11
About Sitel Sitel is a world leader in outsourced customer care services... Sitel is a world leader in outsourced customer care services, including some of the most advanced contact centers in the world. With over 26 years of industry experience, Sitel has twice been ranked as the top overall call center outsourcing provider in Datamonitor s annual Black Book of Outsourcing survey. Sitel has also been ranked in the Leaders Quadrant in Gartner s Magic Quadrant: Customer Management Contact Center BPO, Worldwide, 2010. Sitel s 56,000 employees provide clients with predictable and measurable return on their customer investment by building customer loyalty, increasing sales and improving efficiency. Sitel s solutions span 135+ domestic, nearshore, and offshore centers, speaking 36 languages in 26 countries. Page 11