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Why Session Border Controllers are Crucial to IP-based Contact Centers

Posted by Paul Desmond

Jul 31, 2015

We’ve written a number of times about the changes coming to contact centers, from their support for customers using all sorts of mobile devices to the ins and outs of cloud-based contact centers. No matter what contact center topic you choose, chances are a common denominator is the center is shifting from a TDM-based infrastructure to IP.busy_contact_center_agents

The shift has been taking place for quite some time and the benefits in terms of cost reduction and more flexible solutions are quite clear. But to fully realize those benefits companies need to be cognizant of a key requirement: they’re going to need a session border controller (SBC).

Why IP is Taking Over in the Contact Center

One of the biggest reasons for the shift to IP is to take advantage of SIP trunking, which is far more cost-effective than TDM-based PRI or T1 lines, says Mykola Konrad, VP of Go To Market and Strategic Alliances for Sonus Networks.

Lots of contact centers consist of a number of agents in one location and many more in one or more other locations, all working in concert. That means the company needs PRI lines coming in to each location.

Dig Deeper:  Read Session Border Controllers for Dummies to learn more!

Often the lines are over-provisioned, the result of a contract signed years ago before call volumes dramatically changed. Or it could be because PRIs and T1 lines are usually sold in rather large chunks, such as 16 or 24 circuits, making it difficult for a company to secure only the capacity it needs.

With SIP trunking, on the other hand, companies can buy the exact number of lines they need, Konrad says. Configuration is likewise more flexible. Companies can configure all calls to come in to a central call center, then route them out over the company WAN to agents at other call centers as appropriate. Should the primary call center go down, all calls can be quickly routed to an alternate center, providing improved reliability.

Whenever a company is using SIP trunks, it should also be using an SBC. Here are three reasons why.

How SBCs Help Protect Investments in Legacy Contact Center Equipment

Even after a company implements IP and SIP trunks, there’s a good chance it’ll still be dealing with some amount of legacy, TDM-based equipment. Companies are heavily invested in their interactive voice response (IVR) systems, for example. “They’ve spent years honing them and optimizing menus,” Konrad says. Even fax machines still have a place in some call centers.

Such devices rely on traditional telephone tones to work – press 1 for an agent and so on. Those tones, known as DTMF, have to go through a conversion process – known as interworking – in order to work with SIP trunks. The same may be true even for SIP equipment, since the standard may be implemented slightly differently by an equipment vendor and a carrier, for example.

An SBC performs this interworking function, ensuring all versions of SIP play nice together and converting the signals coming over the SIP trunks into the DTMF tones that the IVR and fax machines expect.

Providing Security for IP-based Call Centers

As companies move to IP and SIP trunking in their call centers, they also need to address security. Because all communications are now IP-based, the contact center is susceptible to all the usual sorts of cyber attacks, including denial-of-service (DOS) attacks that can render a call center unreachable to customers.

An SBC is able to identify illegitimate or malformed packets and deny them entry, effectively policing against malicious attacks, including DOS attacks, a topic we covered in a previous post.

SBCs Help Reduce Phone Company Fees for Contact Centers

Finally, SBCs can help companies save money in their contact centers even beyond what they’ll save using SIP trunks, Konrad says. A company with contact centers at two or three different sites will occasionally need to transfer a call between sites, such as to a different department.

“Typically that transfer goes back out over the PSTN, to another 800 number, then back to the same company,” he says. “Contact centers pay a take-back-and-transfer fee to the phone company each time that happens.”

While the fee may be just a few cents per call, it can quickly add up. An SBC eliminates the fee by enabling calls to travel over SIP trunks to the company’s own corporate WAN, so they never have to use the PSTN. In addition to saving the fee, routing the calls in this manner also reduces the possibility that calls will be dropped, he notes.

Topics: Voice, Contact Center, Business Case, Security, SIP, Session Border Controller

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