# Configuring Bandwidth IP Authentication Trunk
Before proceeding with the next steps, you need to purchase a DID on the [Bandwidth ](https://www.bandwidth.com/)platform.
***
### Overview
Bandwidth must be configured as an **IP-Based Trunk** at the PortSIP PBX System Administrator level.\
Once the trunk is successfully created, it can be shared with one or more tenants, and DIDs can be assigned through a DID Pool.
***
### Configure a Bandwidth IP Authentication Trunk in PortSIP PBX
#### Step 1: Create an IP-Based Trunk
1. Sign in to the **PortSIP PBX Web Portal** as a **System Administrator**.
2. From the left-hand menu, navigate to:\
**Call Manager > Trunks**
3. Click **Add** to open the trunk type menu.
4. Select **IP Based Trunk**.
***
#### Step 2: Configure Basic Trunk Settings
1. Enter the following information:
* **Name**\
Enter a friendly name for the trunk (for example, *Bandwidth Trunk*).
* **Brand**\
Select **Bandwidth**.
* **Hostname or IP Address**
* Contact the **Bandwidth Support Team** to obtain the IP addresses for your Bandwidth SIP trunk.
* Bandwidth typically provides **two or more IP addresses**.
* Enter the **primary IP address** in the **Hostname or IP Address** field.
* Add the remaining IP addresses under **Associated IP Addresses**.
**Example**
```
216.82.224.202
216.82.225.202
```
2. Click **Next**.
***
#### Step 3: Configure Trunk Options
1. Review the trunk options and adjust settings as needed.
2. Configure the following field if required:
* **Max Concurrent Calls**\
Defines the maximum number of simultaneous calls PortSIP PBX can establish using this trunk.\
Set this value based on your capacity planning and service agreement with Bandwidth.
> **Best Practice**\
> Keep all other options at their default values unless Bandwidth has provided specific requirements.
3. Click **Next**.
***
#### Step 4: Assign Tenants and Configure the DID Pool
1. Select one or more **tenants** to grant access to this trunk.
2. Configure the **DID Pool** to assign Bandwidth DIDs to tenants.
> **Important**
>
> * Each DID can be assigned to **only one tenant**.
> * A tenant can use **only the DIDs in its assigned DID Pool** to:
> * Create inbound rules
> * Create outbound rules
> * Configure outbound caller ID for extensions
**DID Pool Format Examples**
The DID Pool may include:
* A single number
```
16468097065
```
* Multiple individual numbers
```
16468097065;16468097066
```
* A range of numbers
```
16468097065-16468097066
```
* A combination of ranges and individual numbers
```
16468097065-16468097066;16468097070-16468097080
```
3. Click **OK** to save the configuration.
***
#### Expected Result
* The Bandwidth IP-Based Trunk is created successfully.
* In the trunk list, the status displays as **Online.**\
(for **IP-Based Trunks**, the status always shows *Online*).
***
### Next Steps
The Bandwidth Register Authentication Trunk is now ready for use.
You can proceed to:
* Configure outbound call routing rules
* Configure inbound DID routing
* Assign outbound caller IDs
Refer to the next guide section: [Configuring Outbound & Inbound Calls](/portsip-communications-solution/configuring-sip-trunks/bandwidth-sip-trunk/configuring-outbound-and-inbound-calls.md).
---
# 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/configuring-sip-trunks/bandwidth-sip-trunk/configuring-bandwidth-ip-authentication-trunk.md?ask=
```
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.