When there is an incoming or outgoing call, a CIC is marked busy. In ISUP, each line is a circuit identified by a circuit identification code (CIC), with dedicated bandwidth. PSTN uses the ISUP protocol for Signaling. The telephone line in our home for PSTN is a trunk with one line only.Įach communication line in the group is called a circuit. Because for each call, a line is allocated from the trunk. But at the same time, multiple customers can be served. For example, in a call center, all customers dial the same customer support number. A long-distance call was called a trunk call.Ī group of communication lines is a trunk. You may have heard about it in the olden days.

What is the trunk in telecom? What is a trunk?Ī trunk is a widespread term in telecom. SIP Uses, service of underlying TCP/IP or UDP/IP. When you dial a number from a SIP phone, first a session is established after that, the phone does a voice sampling and converts it into network protocol messages. The primary endpoint information is the IP address and port. SIP does signaling to set up a media session and other protocols e.g GTP carries media frames.įor setup, a session, sip protocol messages carry, media endpoint information in session description protocol ( SDP) as payload. One is a signaling channel, and the other is a media or voice path. There are two types of channels/paths are in communication. A media session can be for voice, video fax, etc. SIP is a signaling protocol for establishing, modifying, and terminating a media session over the IP network. What is Session Initiation Protocol(SIP)? To explain better, we will explain each component in detail. SIP trunking has two parts one is SIP protocol, and the other is trunking. With SIP trunking, one can have a cost-effective, scalable, and convenient alternative for existing PSTN/ISDN lines.

Sip trunking is the technology that enables VoIP for business. With SIP trunking, one can have a cost-effective, scalable, and convenient alternative for existing PSTN/ISDN lines.Īlmost every industry requires a large call volume for business.

The IP phones connect to the PBX for receiving and sending calls outside the office premises.Īlmost every industry requires a large call volume for business. A PBX connects to a SIP trunking provider over the Internet. SIP trunking is a new and convenient means of communication using VOIP for a high concurrent call volume. What is SIP trunking? What is trunk- Sip Trunking Vs.

Sip trunking explained