With increase in average broadband speed and its usage, VoIP has become preferred medium of communication for large enterprises. As the communication happen in digital form via IP, you can use IP communication for text, voice and video communication, well in that case name will change from “Voice over IP” to “Video over IP”.
Let’s check the technology, its usage, benefits and its limitations.
To setup a basic VoIP communication, businesses need an IP PBX, LAN Setup, IP phone or SIP phone. An IP PBX(private branch exchange) is local telephone switching with an enterprise that switches calls between the users with the help of extension line. Few IP PBX also have capability of a VoIP gateway, they can also switch calls between a VoIP call and a PSTN call, or between two traditional telephone users in the same way that a conventional PBX does. Note – In many countries mixing of PSTN and VoIP is not permitted
What is SIP – SIP (Session Initiation Protocol) is a signaling protocol widely used in multimedia communication sessions such as voice and video calls. SIP is one the protocol to enable VoIP. It defines how messages can be send between two endpoints and controls the call initiation, termination and signaling. It is also used for other data applications like video conferencing, instant messaging, media distribution. SIP was developed and standardized by Internet Engineering Task Force (IETF).
A typical call flow in VoIP & role of SIP and SIP trunk
|PRI (Primary Rate Interface) is a physical connection to the PSTN over a dedicated line that only serves voice transmission.||SIP (Session Initiating Protocol) Trunk is a connection between ITSP and enterprise, it can be used for voice, chat and video|
|It uses circuit switched model for making voice connections between people||Uses a packet switched model for making communication|
|Number of simultaneous call depend on number of channels. Typically, PRI comes with 30/ 23 channels based upon E1/T1||Number of simultaneous call depend on bandwidth, just need take extra bandwidth if you want to increase number of calls|
|Number of simultaneous call depend on bandwidth, just need take extra bandwidth if you want to increase number of calls||QoS depend on bandwidth and number of users|