by Gary Audin

Connecting Microsoft’s Lync to SIP trunks and SIP qualified devices is a matter of interoperability. Both Microsoft and the SIP vendors/providers need to participate in a thorough structured test to validate their interoperability. The Lync to SIP qualification lists are growing. The enterprise should view the appropriate Microsoft lists so that only the qualified vendors and providers are considered.

This is an ongoing process. Once an interoperability test is successfully completed and the Microsoft qualifications met, then both Microsoft and the vendor/provider will have to ensure that they also update their qualifications. Either side can implement changes to the qualified product or service that will require retesting.

Microsoft has instituted a qualification program. “Unified Communications Open Interoperability Program – Lync Server” http://technet.microsoft.com/en-us/lync/gg131938#tab=5  that contains information about qualified vendor’s products and provider’s services.

The Microsoft site states, “This qualification program for enterprise telephony services and infrastructure ensures that customers have seamless experiences with setup, support, and use of qualified telephony infrastructure and services with Microsoft’s unified communications software including Lync Server and Exchange Server.

The qualification program specifications are based on industry standards. The program also defines:

• Interoperability requirements for Lync Server and Exchange Server Voice Mail
• The testing requirements for Lync Server and Exchange Server Voice Mail for interoperability
• A quick start guide for installation, set-up and configuration
• Publication of release notes concerning known issues
• A support process for Microsoft and the vendor/provider documentation
• Standards for enterprise class audio quality, reliability, and scalability

The program is divided into six parts. The first two parts are of greatest interest for SIP trunking implementers listing service providers and Session Border Controller (SBC) vendors. The enterprise can provide the SBC or the SBC can be part of the service provider’s configuration.

• SIP Trunking Services qualified for Lync Server 2010 – The list contains 31 domestic and international providers. They are listed as qualified, Office 365 Dedicated and qualified with Secure Real Time Protocol (SRTP) and Transport Layer Security (TLS).
• Session Border Controllers qualified for Lync Server 2010 – Only three vendors are qualified, Acme Packet, Audiocodes, and NET. The qualified products and software versions tested are listed.
• Direct SIP: PSTN Gateways and IP-PBXs Qualified for Lync Server – 16 vendors are listed (Audiocodes to Sonus) supporting multiple products per vendor including basic to enhanced gateways and IP PBXs. The products fall into two categories, qualified and qualified with SRTP and TLS.
• Supported IP-PBXs for Microsoft Lync Server 2010 – Three vendors are listed, Alcatel-Lucent, Avaya and Cisco. This section also has notes on the required configurations and limitations.
• Survivable Branch Appliances Qualified for Microsoft Lync Server 2010 – Five vendors are listed with their qualified firmware.
• E-911 Service Providers and ELIN Gateways qualified for Lync Server 2010 – There are two service providers listed, 911 Enable and Level 3. There are two Emergency Location Identification Number (ELIN) Gateway vendors Audiocodes and 911 Enable listed.

The Microsoft site states that “The testing focus of the program is designed to ensure that vendors providing interoperability with Microsoft unified communications solutions do so in a consistent and supportable manner, including SIP and signaling support used with the Mediation Service in Lync Server and the Voice Mail role of Exchange Server.”

The fact that a product or service has qualified does not mean that the Lync connection will be a simple plug-and-play effort. The enterprise will still have to follow the documentation and configure the Lync end properly. The enterprise must also ensure that the correct software version or release is being used for the Lync connection. However, since these vendors and providers have been qualified, there will be vendor and provider experts available for support.