Ingate Systems Smooths the Path Between VoIP Networks

By straightening out standards mismatches and NAT traversal issues, Ingate systems brought a smile to the faces of VoIP admins at a large dental group.

By Adam Stone | Posted Jan 15, 2009
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Cavities are more than just a pain in the mouth. With more than half of 5- to 9-year-old children sporting pitted pearlies, the Surgeon General has called oral care the most unmet medical need among American children.

Kool Smiles aims to fix that. With offices in more than a dozen states, the Atlanta, GA-based group makes dental care available to children in under-served communities. In an effort to spend less on infrastructure and more on dental hygiene, the company recently upgraded its traditional phone service to a SIP-Trunking system.

Bandwidth.com is the carrier, with a 3Com VCX as PBX. Between the two sits an intermediate layer, and here’s where it gets interesting. Didja know? There’s no rule that says your carrier and your PBX are going to be able to communicate with one another, and in fact they often don’t.

This is where the intermediate layer comes in, as supplied by Ingate Systems. That company’s SIP trunk software solutions and Ingate SIParator are helping the Kool Smiles network overcome a pair of common hurdles on the way to SIP connectivity.

The SIParator is supposed to “normalize the SIP signaling between the IP-PBX and their SIP trunking service provider,” Ingate says. The problem here has to do with standards. There are multiple ways to route traffic through a SIP network, and not everyone takes the same approach, explained Ingate Systems President Steven Johnson.

“Service providers may have adopted one method of handling certain call scenarios, but the IP-PBX vendor may have implemented a different, but still standard, method for the same call scenario,” he explained.

In one common model, calls travel by “re-invite,” a method of transfer that takes a call and reinitiates it in order to complete the transfer. Then there is the “refer” method, which treats a call as being internal to the LAN, thus allowing it to transfer between internal users without the service provide necessarily knowing about it.

As a translator between the two approaches, Ingate has been identified as a preferred normalization agent by ShoreTel, 3Com, Iwatsu, Mitel and Nortel’s SCS500 Johnson said.

In the case of Kool Smiles, 3Com identified a potential conflict early on and advised the customer to bring Ingate into the game, Johnson said.

The translation issue is one aspect of a SIP implementation that Ingate was able to address here. The second potential conflict has to do with Network Address Translation (NAT) traversal, whereby an existing firewall effectively won’t allow calls to proceed beyond the user’s public IP address. NAT traversal problems will stop a call from reaching the PBX or from extending from the PBX out to extensions.

“Unless you can solve that NAT traversal issue and normalize the SIP traffic between the carrier and the PBX, you are going to get a lot of one-way audio, a lot of dropped calls,” Johnson said.

Of course, there are other ways to address these questions besides through the Ingate solution. When it comes to translation, for instance, an end user or integrator can determine in advance whether a PBX and a carrier are going to be able to intercommunicate, and only work with compatible pairings.

In addition, the SIP Forum has adopted SIPconnect, a connectivity standard that could form the basis of future cooperative solutions between service providers and PBX vendors.

Incorporating the Ingate solution, Kool Smiles has implemented a centralized system to connect all its offices. The call center is using an automated patient reminder system. Kool Smiles Co-founder and Chief Technical Architect Mark Blomquist said the company is looking at the system as a means to gather data for call detail reporting and marketing analysis.

The company may pursue click-to-call for its website, and will also test Secure Real-time Transport Protocol (SRTP) technology, should telecommuters begin using SIP phones to conduct patient conversations, Blomquist said.

That evolution would require a high degree of security, a demand that has not arisen yet. While Ingate could have provided encryption and other security measures at the edge of the network, the medical practice opted not to put these into place for now. HIPPA restrictions set a high bar for information security in medical settings, but the phone system in this case is being used for routines matters such as appointment reminders, and thus did not require a high degree of safeguarding, Johnson said.

For Kool Smiles it all amounts to a significant financial savings. The company has shifted more than 35,000 calls a day to toll-free Internet telephony. By transitioning from traditional telephony to SIP trunking the company says it has reduced its communications costs by 40 percent, achieving ROI in 12 months.

That ought to put brighter smiles on a lot of little faces.

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