What is SIP Trunking? And How Does it Work

A basic introduction to SIP trunking explaining the concepts of trunking and

SIP, as well as the benefits of SIP trunking.

SIP trunking is a is a basically a type of communication system which allows organisations to replace all of their traditional phone lines with Voice Over Internet Protocol (VoIP). VoIP systems carry the call over the internet rather than the traditional phone line system. SIP trunking allows VoIP users to call numbers on the traditional phone and mobile networks. If the people on both ends have SIP the system will try to route the entire call over the internet and avoid traditional phone lines entirely.

SIP Trunking

SIP is an internet protocol designed to manage real time communication (RTC). This covers things like VoIP, video chat and instant messaging. An internet protocol is basically a set of rules which govern how devices connected to the internet interact with each other. So SIP is basically a set of rules which allows RTC software/devices to communicate with each other over the internet.

SIP

In telecoms trunking has been around for a long time. Trunking allows an organisation to cut down on the amount of lines it needs. An organisation can have a trunk with a limited number of phone lines, but still have many more phones connected to it’s network than lines. Quite simply, this is because all of the phones don’t need to be used at once, so they are only connected to an outside trunk line when they need to be.

Trunking

A SIP trunking system is made of three parts: ∗ A Private branch exchange (PBX) with a SIP

enabled trunk side.

∗ The enterprise edge component. Either a firewall with SIP support of an edge device which is connected to the firewall .

∗ An Internet Telephone Service Provider (ITSP). This is the SIP equivalent of an ordinary ISP.

The 3 Parts

There main benefit of a SIP trunk system a reduction in costs. Call rates are lower and the exchange systems required are significantly cheaper. SIP trunk systems are also more scalable and flexible, and have a wider range of capabilities including instant messaging and video calling. SIP trunking systems are generally cheaper than their traditional alternatives, however it should be noted that this is not always necessarily the case.

Benefits