SIP Trunking and Microsoft Communications Server (OCS)

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Alan Percy
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SIP Trunking and Microsoft Communications Server (OCS)

Security, Survivability and Choice - words that are very near and dear to most IT managers, but what do they mean in Microsoft Communication Server deployments?   
  • Security - knowing that your business is protected from malicious attack by outsiders that might have an axe to grind or trying to steal sensitive information.  
  • Survivability - making sure you have a disaster recovery plan to keep the business operating when things do go wrong.
  • Choice - having the freedom to make changes to and select your service provider based on price, service, quality or new capabilities.
Until recently, if you were in the process of deploying Microsoft's Communications Server it was pretty difficult to use SIP Trunking and still maintain security, survivability and choice.   Securing SIP Trunks requires a Session Border Controller at the enterprise from one vendor, while survivability required separate media gateways and back-up PSTN telephone lines.  The number of certified SIP Trunking vendors that have gone through the arduous certification program is fairly small and as a result, severely limits the choices available to most businesses.


With today's announcement of UcSIPT from AudioCodes, businesses deploying Microsoft Communications Server can leverage an AudioCodes E-SBC - one single device that has the ability to:
  • Secure SIP Trunks - with an embedded Enterprise Session Border Controller (E-SBC), protecting the business against common SIP-based network attacks coming from the Wide Area Network that traditional firewalls are unable to mitigate.
  • Provide Interoperability with SIP Trunks - via a back-to-back user agent with transcoding, virtually any SIP Trunking service provider can be used with Communications Server.
  • Deliver Survivability - with an optional integrated media gateway modules, traditional PSTN lines can be maintained and used as back-up circuits in cases where there is a failure in the SIP Trunk connectivity or service.
As an example of a typical deployment, Joe LeNoach, IT Manager in Alutiiq offers the following assessment of his experience in using the Mediant 1000 MSBG to interface his Office Communications Server system with a SIP Trunking service provider:  "We have recently decided to use the AudioCodes Mediant 1000 for connecting our network to the Verizon SIP Trunking service," said Joe. "We were looking for a solution to securely connect the Microsoft Office Communications Servers installed in our branches using a cost-effective SIP trunking service. AudioCodes Mediant 1000 provided the required mediation services to implement this solution quickly and cost-effectively."

Jeff Kahn. Chief Strategic Officer and Nimrod Borovsky, VP of Marketing at AudioCodes discuss the UcSIPT strategy and solution set in this video.

It looks like businesses are one step closer to having the choice of SIP Trunking service provider, security and survivability without cobbling together a number of different appliances from different manufactures.  

For more information on UcSIPT, visit:

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