# 7 Trunk Management

Session Initiation Protocol (SIP) trunking is a digital method for making and receiving calls—and other real-time communications—over an IP network using SIP, an application-layer signaling protocol. In this context, **“trunking”** means aggregating multiple concurrent call paths (channels) into a single logical connection between your PBX and a carrier or service provider.

A SIP trunk typically provides **VoIP connectivity between an on-premises PBX and the Public Switched Telephone Network (PSTN)**. For example, an office may run an internal PBX for extension-to-extension calling. By connecting the PBX to a SIP trunk, users can place and receive external calls to/from the public telephone network.

SIP trunking is commonly used to **establish, manage, and terminate call sessions** (call setup, mid-call signaling, and teardown). It is widely adopted because it’s flexible, scalable, and standards-based—helping organizations connect their phone system to external calling services without traditional physical trunks.

PortSIP PBX supports a wide range of mainstream SIP trunk providers worldwide, including (but not limited to):Topics Covered

This article includes the following topics:

* [Vonage](https://www.vonage.com/)
* [QuestBlue](https://questblue.com/)
* [VoIP.ms](https://voip.ms/) 
* [Voxtelesys](https://voxtelesys.com/)
* [Flowroute](https://flowroute.com/)
* [Skyetel](https://skyetel.com/)
* [Wavix](https://wavix.com/)
* [Bandwidth](https://www.google.com/aclk?sa=l\&ai=DChcSEwjP4Z7F04mGAxWv1MIEHcavBZsYABAAGgJwdg\&ase=2\&gclid=CjwKCAjw0YGyBhByEiwAQmBEWt0-86eUzdm8dvIhQPbhC0MFJ_iY0a-UAgyis1Kao874WgSy0MGNIhoCsocQAvD_BwE\&ei=ioRBZu2MC6yF0PEP0NKHiAI\&sig=AOD64_2iLhFzhgCJBcCnSRVqnrIcSWO_Vg\&q\&sqi=2\&nis=4\&adurl\&ved=2ahUKEwjt-ZXF04mGAxWsAjQIHVDpASEQ0Qx6BAgJEAE)
* [Twilio](https://www.twilio.com/en-us)
* [Telnyx](https://telnyx.com/)
* [Callcentric](https://www.callcentric.com)
* [Telstra](https://www.telstra.com.au/)
* [CM.com](https://www.cm.com)
* [Aire Network](https://airenetworks.es/)
* [Gamma](https://gammagroup.co/)
* [VoIP Innovation](https://carrierservices.sangoma.com/)
* [VoiceMeUp](https://www.voicemeup.com/)
* [SIPTRUNK](https://www.siptrunk.com)

### Topics Covered

This article includes the following topics:

* [Configuring SIP Trunk](https://support.portsip.com/portsip-communications-solution/portsip-pbx-administration-guide/7-trunk-management/configuring-sip-trunk)
* [Handle Outbound Calls Through SIP Trunk](https://support.portsip.com/portsip-communications-solution/portsip-pbx-administration-guide/7-trunk-management/handle-outbound-calls-through-sip-trunk)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://support.portsip.com/portsip-communications-solution/portsip-pbx-administration-guide/7-trunk-management.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.