SIP trunking is a cost-effective solution for businesses as it reduces communication expenses. When paying for a SIP trunk, the primary consideration is usually the number of channels in the trunk. A channel represents the data capacity required to make one concurrent call on a network. The more channels you have, the more calls can be made and received simultaneously. Think of these channels like lanes on a highway, with each lane capable of containing a certain amount of cars (data). If traffic increases, adding more lanes helps smooth out the flow. Similarly, adding more channels to a SIP trunk allows for more data usage in making calls. The cost of a channel depends on the provider, so it's essential to compare prices and choose a suitable plan.