This content is part of the Conference Coverage: Enterprise Connect 2016: Special conference coverage
Get started Bring yourself up to speed with our introductory content.

Avoid these four SIP deployment pitfalls

Implementing SIP trunking can be a daunting task for many organizations. But enterprises can take certain steps to ensure their SIP deployment is relatively smooth. Industry leaders at Enterprise Connect urged organizations to heed these four common SIP pitfalls:


While SIP deployments promise cost savings, organizations must watch out for surprise costs. Most SIP trunking providers detail their costs on their pricing page, but additional fees are often found in a thorough reading of a contract, said Melissa Swartz of Swartz Consulting.

Swartz cited one company that discovered its provider put in the contract that every call to 911 would be $75. Other providers charge a fee for organizations that reach a certain percentage of calls that are less than 15 or 18 seconds, she said.

“They’re not deliberately hidden, but you have to read the contract,” she said.

To avoid pricing surprises, Swartz recommended running scenarios to estimate your usage, factor in additional costs, like backup, and look for other fees hidden in the contract.

Facilities and Features

Organizations must determine if their carrier is providing trunks all the way down the line and not relying on another carrier for the last mile, Swartz said.

“That’s something that can cause issues because the trunks are not under the SIP provider’s control all the way,” she said.

Organizations must also be mindful of the features offered by SIP providers. “There are words that different carriers use, but they don’t mean the same to each carrier,” Swartz said.

Larry Riba, lead voice engineer at nonprofit financial services firm TIAA, discussed an issue he had with a call-recording vendor. When TIAA was planning its SIP migration, the nonprofit’s call-recording vendor said it could support call recording with SIP.

“It was a terrible failure,” he said. Luckily, the issue was discovered early in the migration process, but it took months to fix and delayed the migration.

Configuration and Security

The configuration of session border controllers (SBCs) and firewalls must be done carefully to prevent service disruption. Swartz said if there’s a problem with the SIP service, the firewall should be the first place to check.

“If you’re not getting a call, it’s a firewall setting,” she said.

Properly configuring 911 services should also be a priority, to ensure that first responders are directed to the correct location. This is especially important for organizations that have multiple locations with a centralized SIP deployment, Swartz said.

Organizations should also make sure every part of their SIP deployment is secured properly, including fax lines and analog phones.

“You want an SBC that can handle all kinds of stuff,” said Mykola Konrad, vice president of product management at Sonus Networks.

Organizations will have different security needs depending on whether their SIP trunking service is delivered over an MPLS or broadband line, he said. The best thing an organization can do is include the IT department security expert early in the migration process.

“As soon as you’re doing something that says ‘IP’ on it, you have to have the security guy bless whatever the project is,” Konrad said.

Failover and Disaster Recovery

With SIP failover and redundancy, organizations must make sure their provider can offer business continuity.

“You need to understand from a carrier perspective how far they can see and what would trigger an automatic failover,” Swartz said. Organizations must quiz their provider prior to their SIP deployment on what triggers failover, if DID and toll-free numbers are included in call rerouting, and, if the organization uses a backup carrier, how SIP calls transfer to the backup.

Failover and disaster recovery should be seamless, said Ari Sigal, product marketing manager at Twilio.

“Some disaster recovery is simple call forwarding, but that doesn’t keep the business operating the way it typically does,” he said.

Sigal said Twilio uses APIs to allow real-time decision making and the ability to automate failover and call rerouting based on certain conditions.

SIP trunking offers big benefits to organizations, but “you’ve got to know what you’re doing,” Swartz said.