SIP trunking is a term that often comes up when talking about telephony. But what is a SIP trunk? How does SIP work and how can your business benefit from the technology? We clarify the concept and the benefits of the technology.
What is SIP?
SIP stands for Session Initiated Protocol. It is the protocol that enables telephony and VoIP services. The latter is also known as IP telephony, broadband telephony and internet telephony. A SIP trunk is a virtual phone line that allows you to make and receive calls over the internet. Both voice and video calls as well as chat messages can be controlled by a SIP trunk.
This can be compared to making a call over the traditional, analog telephone network, also known as the PSTN (Public Switched Telephone Network). It is a network made up of copper wires and requires a physical connection between two points to make a phone call. For a long time, it formed the backbone of all telecommunications.
But those days are coming to an end. Instead, the demand for digital telephony services and cloud-based telephony solutions, SIP trunking, IP telephony and cloud switches is growing all the time.
What is a SIP session and a SIP phone?
A so-called SIP session is simply a call or session via a SIP trunk. SIP allows you to establish sessions between two parties, a receiver and a sender. You can also park and forward calls and add more participants during the session.
A SIP phone is the same as a VoIP phone or a softphone. They are just different names for phones that you can use to make VoIP calls. SIP phones can be both software and hardware based. A hardware SIP phone works much like a regular phone but it can receive and make calls over the internet instead of the traditional phone network. Software-based SIP phones can instead allow computers to act as phones.
How a SIP trunk works
A SIP protocol is text-based and similar to an HTTP protocol. SIP is the industry standard for communicating via voice and video over the internet or an intranet. SIP in turn uses VoIP to send information over the internet. So you use a SIP trunk line instead of a traditional phone line whether you are calling your colleague in another office or video chatting with someone internally.
When an incoming call arrives, it is routed through your current phone system using signaling information that allows your phone to know where to send the call.
With SIP trunks, you can make calls over the internet to anyone – whether they use VoIP or PSTN. SIP trunking works with a SIP-compatible telephone exchange. It thus replaces the traditional copper lines.
A SIP trunk can handle multiple SIP channels/SIP lines and each SIP channel handles one call, just like a traditional phone line. However, with old phone lines, it was time-consuming and difficult to add more channels within the company. A SIP trunk can handle an unlimited number of channels so you only need one SIP trunk. How many SIP channels you need depends on how much you call within the company.
What is required to use SIP trunking?
All you need is a connection in the form of an internet subscription and a SIP-compatible PBX to which the traffic can be sent. Most new PBXs are SIP-compliant, but if you have an older PBX designed for the old telephone network, you will need to upgrade to an IP PBX.
The main benefits of using SIP trunking
A major advantage of SIP trunking is that it is future-proof. The internet will still be around in 100 years – although it might be designed differently. Regardless, there will be opportunities to connect calls in a similar way for a long time to come.
SIP trunking is also a powerful and secure technology. No one wants their calls to be hacked, whether it’s a phone call or a video conference. Should your connection go down, SIP trunking ensures that your calls are automatically rerouted after a few seconds of interruption.
Reduced costs
There are many advantages to making calls over the internet instead of the analog phone network. Perhaps the most obvious difference and what attracts many is the reduced costs SIP can offer. Some reasons why you can reduce the cost of telephony include the following:
- Lower upfront costs – you don’t need to put in as much money from the start.
- Lower call costs – you make free calls between your connected offices.
- Reduced number of fixed subscriptions.
- You don’t have to pay for maintenance for a specific operator’s lines.
- Lower monthly line and DID rent as you don’t have to pay to switch up to more lines.
- SIP trunking allows you to use local and toll-free numbers that go to the same SIP trunk.
- You only need to maintain one network because SIP trunking runs over your data network. You can thus cut down on the resources you had to manage the PSTN network.
Improved flexibility
SIP trunking is a scalable solution that allows you to be flexible. If your busiest period is around Christmas and New Year, you can scale up when you know call traffic will be more intense and then remove the extra lines during the off-season. If you want to add more phone lines, it will take a long time to install if you use the traditional phone network.
With SIP trunking, you are not dependent on a geographical location but you make free calls between all offices, regardless of the country. So it doesn’t matter if your employees work from home or abroad – the cost of the calls is free when you use your internet subscription.
With SIP trunking, you can instead quickly add more trunks and channels with DID (Direct Inward Dial) – it usually only takes a few minutes to fix. Since SIP trunking enables DID, everyone in the office can have their own SIP line. As we mentioned earlier, there’s also no problem if you move offices or open new ones – you can still use the same numbers.
Want to know more?
At Telavox, we can help you with everything related to SIP, VOIP, mobile telephony and PBX services. Book a free demo and learn more about the possibilities!
