Skip to main content


What is a SIP trunk channel?


July 2, 2019


December 8, 2021


We know that SIP trunking can reduce the amount of spend for a business. But when you pay for a SIP trunk, what are you actually paying for?

It’s very rarely the SIP trunk itself, which even when you get down to the nitty-gritty of it, is more of a concept than an actual thing you can buy. It can be the amount of time you spend on a call, split into outbound and inbound, with different prices for each. But more often than not, your main consideration is the channels in your SIP trunk.

If you’re looking for a top-to-bottom explanation of SIP trunks, SIP trunking and how they operate, take a look at our ultimate guide.

The Bandwidth definition

In telecoms, a channel is the data capacity required to make one concurrent call on a network. The more channels you have, the more calls you can make and receive.

So if you have 10 people in your business calling customers and 10 customers calling your business to get customer service, you’re using 20 channels.

The highway explanation

This is our favorite explanation and one that is used a lot in the telecoms space. The idea is to think of your SIP connection to the Bandwidth network like a highway. On the highway, you have multiple lanes, each capable of containing a certain amount of cars.

These lanes are like your channels, with the cars being your data. If you start connecting more towns to your highway, you’re going to increase the number of cars, eventually leading to congestion. But, if you add more lanes to the highway, you’re going to smooth out the traffic and avoid jams.

This is similar to adding channels to your SIP trunk. The more data you use to make calls, the more channels you need.

So how many channels are there?

Well, unlike our highway example, there’s no limit on the number of channels you can have in a SIP trunk. So if you have one million people calling you, you’re going to need one million channels at a minimum.

How much is a channel?

That depends on your provider. Different providers have different SIP trunking pricing, so check out Bandwidth’s pricing page to see what our pricing is, and how it stacks up to the competition.

If you’re looking for a specific quote, get in touch with our team.