VoIP Glossary

What is SIP Trunking?

SIP Trunking: SIP trunking (Session Initiation Protocol trunking) connects your existing on-premise PBX or phone system to the public telephone network via the internet. It replaces traditional ISDN/PRI phone lines with a cloud connection — dramatically reducing telephony costs.

How It Works

A SIP trunk is a virtual phone line that carries voice calls as IP data. Your PBX connects to VestaCall's SIP trunking service via a SIP-compatible IP connection. Calls route through VestaCall's network to reach any phone in the world. You pay per channel (simultaneous call capacity) rather than per physical line.

Business Use Cases

Companies with existing PBX systems use SIP trunking to add VoIP capabilities without replacing hardware. Large enterprises use SIP trunks to consolidate telephony costs across multiple offices. Call centers use SIP trunking to scale call capacity up or down based on demand without leasing physical lines.

How VestaCall Uses SIP Trunking

VestaCall offers enterprise SIP trunking with unlimited channels, local and toll-free DID numbers, 99.999% uptime SLA, and automatic failover. Integration with Cisco, Avaya, Asterisk, and most SIP-compatible PBX systems.

VestaCall SIP Trunking

Frequently Asked Questions

How many channels do I need?
A channel supports one simultaneous call. A business with 50 employees typically needs 15–25 channels (assuming not everyone calls at once). VestaCall's team can help calculate the right number.
Is SIP trunking the same as VoIP?
SIP trunking is a specific implementation of VoIP used to connect PBX systems to the internet. VoIP is the broader technology; SIP trunking is a protocol and deployment method.
What hardware do I need for SIP trunking?
You need a SIP-compatible IP-PBX or a SIP-capable router/gateway. VestaCall supports all major PBX vendors including Cisco, Avaya, 3CX, and FreePBX.
Can I get SIP trunking with DIDs in multiple countries?
Yes. VestaCall provides SIP trunking with local DID numbers in 100+ countries, letting you present local caller IDs in every market you serve.