Terms and definitions in messaging

Multichannel messaging service is based on a variety of telecommunication and Internet technologies. In the description of services, we often use abbreviations that may not always be known to you. Here we have compiled a glossary of terms and definitions used in the industry.


Session Initiation Protocol is a communications protocol for signalling and controlling multimedia communication sessions. It is commonly used by Internet (IP) telephony systems (Voice over IP) but is sometimes used to set up professional audio and video over IP connections. AES-67 mandates use of SIP for connection management, with other protocols such as Bonjour and NMOS IS-05 being optional. SIP aims to provide call functions and features similar to normal telephone network. The features that permit familiar telephone-like operations (i.e. dialling a number, causing a phone to ring, hearing ring back tones or a busy signal) are performed by SIP proxy servers and user phones. A text based protocol called SDP is used to describe the functionality provided by each network node. The SMPTE ST 2110-10 standard for high bitrate professional media over managed IT networks mandates use of SDP. Sometimes, a device called a Session Border Controller is used at the border between service providers, is used to provide extra features including security, NAT, QoS and priority.