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Case Study: SIP Trunking in the Contact Center at Triton Technologies

Triton Technologies is a team of direct response professionals specializing in soft-offer conversion, campaign analysis, and revenue optimization. Triton's goal is to provide their customers with higher close rates, larger average tickets, and a superior return on investment. The staff at Triton is rigorously trained and is widely regarded as some of the best in the business. Headquartered in South Easton, MA, Triton has sales agents in their main office and in Phoenix, AZ.

If you have ever called a toll-free number to order a product from either a TV, print or on-line advertisement, you very well may have ended up talking to a Triton Technologies agent to complete your order.

Managing this inbound call volume is a SIP-based contact center using Interactive Intelligence Customer Interaction Center (CIC). The contact center plays an important role in routing each caller to a trained agent who is knowledgeable about that product or service. Determining which product the caller is interested in is often based on the number the caller dials--Triton handles calls from thousands of toll-free numbers, each representing different products or campaigns.

Challenge
Until earlier this year, Triton Technologies directed all their call traffic to a number of TDM T1 PRI trunks from a major national carrier using media gateways. The media gateways terminate the TDM T1 PRI circuits and convert the call traffic to SIP for handling by the Interactive Intelligence CIC servers. This configuration was and continues to be highly reliable, but is also rather costly. The toll and circuit charges for the T1 PRI circuits were an easy target for cost reduction.

Triton Technologies saw an opportunity to reduce operating costs with SIP Trunking for both the toll-free inbound and outbound long distance calling. After careful consideration, they chose two different SIP Trunking carriers--a national competitive SIP Trunking carrier for the inbound traffic and an aggressive, but smaller SIP Trunking carrier for outbound traffic. This choice and strategy were important due to the large number of toll-free numbers used and the need for national coverage for inbound calls. It was also felt that maintaining choice in selecting competitive carriers would be valuable in the future--allowing Triton to make changes in carriers as the market or needs shifted.

With the SIP Trunking service providers selected, a search had begun for the tools needed to secure the trunks and provide interoperability with the carriers--a job for an Enterprise Session Border Controller (E-SBC). The E-SBC would support security on both signaling and media planes, each with separate IP addresses--a limitation that a traditional firewall could not address. The Enterprise Session Border Controller would also need access control list features to limit the source of incoming calls to the SIP Trunking providers--avoiding the potential for exploitation by unauthorized users.

Another challenge for the effort was interoperability with Triton's Interactive Intelligence CIC system and the two SIP Trunking carriers selected for the project.

Solution
To provide an interface to the two SIP Trunking carriers, a configuration was developed (as shown in the diagram below) that utilizes two E-SBCs for 150 sessions per device (300 sessions in total). The dual configuration supports both SIP trunking carriers, using DNS in a round-robin load balancing technique. In this redundant configuration, if either one of the E-SBCs failed, the other would continue to handle call traffic, but at half of the total call handling capacity.

The WAN side of each E-SBC was configured with two IP groups, each group supporting one SIP Trunking carrier. The LAN side of the E-SBCs was configured using the parameter set appropriate for Interactive Intelligence CIC.

To maximize security, an Access Control List was configured in the E-SBC feature set, limiting incoming calls to only the prescribed SIP Trunking service providers.

Results
Triton Technologies continues to utilize this configuration today, actively taking customer calls on SIP trunks and using Interactive Intelligence to route and manage their calls. The completed system with the dual load-sharing E-SBCs has been shown to be highly reliable and protects the CIC servers from the daily port probes and other attacks that would otherwise occur via the SIP trunks.

"E-SBCs are the clear choice for maintaining interoperability with our Interactive Intelligence IP-PBX," said Cameron Symonds, Director of IT/TS at Triton Technologies.

As Triton Technologies continues to grow, further expansion of the contact center agent pool is expected, requiring additional E-SBCs in a "rack and stack" expansion.