SMS Case Studies

Seamless Communications: Integrating Two Unified Communications Platforms


Challenge: To integrate architectures from two vendors into a telephony system that creates a seamless user experience.


An independent Defense Department agency was planning to install a Microsoft Lync Unified Communications (UC) platform. However, they also needed to meet a protocol requirement for call preemption that only Cisco supported. The disparate vendors would create challenges with interoperability between the systems and, without the technologies working together, the UC system would lack the capabilities necessary for a robust communications network.


SMS approached the challenge first by applying our high-level engineering skill sets with both Microsoft and Cisco. Our customer requested a Microsoft solution, but also accepted the proposal of a joint platform with Cisco due to a key, necessary feature called Multilevel Precedence and Preemption (MLLP) that Cisco provided. This preemption overrode established calls to ensure that mission critical communications always had an outside connection. In order to integrate the disparate vendor systems, we designed and implemented a plan that included standards-based session protocol (SIP) signaling and session border controllers (SBC’s), as well as intelligent call routing, which was essential to meeting the MLPP protocol. In order to effectively implement the intelligent call routing feature across the platforms, the SMS team worked with the vendors on configurations, bug fixes, patching, and software updates. Meanwhile, the SBC’s were used to understand each vendors’ interpretation of the SIP signaling protocol, and the SMS team translated the protocol to a format that the Microsoft and Cisco phones could understand while also maintaining end-to-end security. The SMS team then designed a call routing system to create a universal dialing plan. The overall solution was the first of its kind in the DoD. SMS continues to manage and operate the systems and infrastructure for this agency.


A seamless, wholly integrated, multi-vendor solution allows for all end-users to use all the Unified Communications features whether they are connected to the Microsoft or Cisco platform, including: telephony, instant messaging, presence, application sharing, and conferencing. Meanwhile, high-ranking officers have the option of preemption and call override as a voice protocol in order to protect national security.