This article originally appeared in the May 2011 issue of INTERNET TELEPHONY.

Large and small businesses are enjoying the benefits of SIP trunking and saving considerable expense. When the installation includes an enterprise session border controller the implementation is fast, integration between the PBX and the service provider is simple, and the service can be more secure than traditional telephony solutions.

But on a recent SIP Forum (News - Alert) Board of Directors call it was evident that some still believe these issues are impediments to adoption of SIP trunking.

The SIP Forum and the IETF recently published SIPconnect 1.1, which defines the best practices for delivering and connecting to SIP trunks. Compliant services and systems will be available shortly.

In the meantime, E-SBCs can resolve the interoperability issue cleanly. They are equipped with back-to-back user agents that enable them to stop and reinitiate calls, and in the process resolve differences that may exist between the PBX (News - Alert) and the service provider with no discernible delays. They also enforce security policies on the SIP traffic.

SIP applications – VoIP/SIP trunking, video and everything under the unified communications umbrella – can be extremely secure, and deployments can take as little as 20 minutes to configure.

Advance planning will go a long way:

·         Until SIPconnect 1.1 is universally supported, E-SBCs can solve interoperability issues between the ITSP and the PBX, making SIP trunking a simple plug-and-play process today!

·         Use the E-SBC to enforce security policies and control access to your PBX and the services you pay for and to block malicious SIP signaling packets designed to attack certain SIP phones, servers or other devices on the enterprise LAN (including the IP-PBX).

·         A good E-SBC should feature an intrusion detection system/intrusion prevention system to protect against DoS attacks based on SIP.

·         Use the E-SBC to authenticate users and prevent unauthorized access to your SIP trunking services by criminals seeking to make expensive phone calls using your account.

·         E-SBCs should employ TLS and SRTP for advanced encryption, confidentiality, message authentication, replay protection and more. TLS-SRTP shields you from eavesdroppers, hackers and spoofers.

VoIP and everything that falls into the UC category are indeed ready for prime time.