Avaya is a global leader in communication systems, applications, and services. Learn about where they've been, where they're headed, and the leaders that are getting them there. The company's communication equipment and software integrate voice and data services for customers including large corporations, government agencies, and small businesses. Its office phone systems incorporate Internet protocol (IP) and Session Initiation protocol (SIP) telephony, messaging, Web access, and interactive voice response. Avaya also offers a wide array of consulting, integration, and other managed IT services. The company sells directly and through distributors, resellers, systems integrators, and telecommunications service providers; more than three-quarters of its sales are made indirectly. Parent company Avaya Holdings filed for an IPO in 2011.