The global business VoIP market is projected to grow to $35 billion in service revenue by 2018, up from from $24 billion in 2013, according to Infonetics Research.
The hosted unified communications business will generate about $4 billion in annual revenue, while hosted PBX services might generate about $8 billion in annual revenue.
Voice over IP (VoIP) and unified communications (UC) services are forecasted to grow from $68 billion to $88 billion by 2018, according to Infonetics Research. These figures include both residential and business sectors as well as access services (SIP trunking) directly related to use of voice and unified communications services.
Other forecasts are not quite so robust. Frost and Sullivan has estimated that 2018 IP telephony and UC services might reach about $8 billion by 2018.