Using Voxbone with Ribbon SBC


We believe setting up business communications should be a straightforward, painless process. That’s why we build our SIP services to play well with whichever communications platform you might use – whether it’s hardware-based or hosted in the cloud, built internally or bought from a third-party vendor.  In this guide we give you the basics to get started.

Special Thanks

Our thanks to our friends at cloud infrastructure specialist ACME UC, for the help they provided in getting this research lab set up and working.

What you’ll need to get started:

  1. A registered Voxbone account with assigned numbers. (Create your account here)
  2. Ribbon SBC

Note: For Voxbone a free-trial account is enough for you to complete a technical validation of our integration with Ribbon SBCs using this guide.

How it works

Ribbon + Voxbone

When a call is received on our platform, we deliver this call to your designated SIP interface through voice URIs. Behind the scenes, we take care of complex
things like least-cost routing, finding the best provider and optimising for maximum call quality. To connect your Voxbone numbers to your RIbbon SBC, we need to establish a SIP interface between the platforms.

This can be done in 2 steps:

  1. Setting Up Inbound Call Routing
  2. Setting Up Outbound Call Routing

1. Setting Up Inbound Call Routing

To set up inbound calls, we need to configure some settings in the Ribbon SBC. Once the destination address is set up there, we can set up a number and direct traffic to this source within the Voxbone platform.

Setting Up IP Whitelisting (Inbound)

First, we need to whitelist Voxbone’s signaling IPs into the Ribbon SBC.

You can find a list of our signalling IPs for all our points of presence (PoPs) here. (outbound only)

These IPs are therefore refered to as {Voxbone}

This should be for UDP/TCP on port 5060/5061 and RTP on UDP 10000-24000

Therefore your firewall rules will look something like this:

From: {Voxbone} To: Ribbon SBC Ports {5060,5061, 10000-24000} Protocol:UDP

From: {Voxbone} To: Ribbon SBC Ports {5060,5061} Protocol:TCP

You also need to configure the Inbound Signalling IPs into the Ribbon SBC, as per the bottom right.

SIP IP Details - Ribbon SBCThese are the Inbound Signalling servers

It’s also worthwhile making sure your configuration has the following central settings for the Voxbone trunks.

SIP SIgnaling Group Details - Ribbon SBC

Setting up a SIP URI

Next you’ll need to setup a URI for us to use. What this looks like will depend on your business setup, how many Ribbon SBCs you have and the level of resiliency you require.

  1. If you’re unsure on the level of resilience you require, we recommend reading this article from our Knowledge Base.
  2. You’ll then need to make sure your inbound call mapping has been completed. This involves ensuring that Codecs / DTMF are configured and that you are correctly handling the +E164 number format we send you, plus anything you need to do to route this to your final end point.

Setting Up a SIP URI To Point At The Ribbon SBC

This is where we set up the SIP interface from Voxbone to the Ribbon SBC. On the Voxbone platform, this is done via Voice URIs.

To be able to differentiate on your Ribbon SBC, we’ll use a reserved keyword on our platform, “{E164}”, so that we can use the same voice URI for many different numbers and detect what number is called/who’s calling.

  1. Log in to your Voxbone account.
  2. Go to Configure > Configure Voice URIs or, if you’re logged in, click here. Then click “New” to create a your Ribbon SBC URI.
  3. Specify the Voice URI as {E164}  or {E164}@YourExternalIP

Adding a Number to the URI So You Can Call it, and Adding an Audio Codec

Now, we need to link one of our phone numbers to the SIP URI just created.

  1. Go to Configure > Configure DIDs or, if you’re logged in, click here.
  2. Use filters to pick a number of your choice to assign for testing and hit “Search”.
  3. Once you’ve picked your number, under the Configuration menu, go to the “Voice” tab and click “Voice URI”. Also, make sure to pick the codecs we set in the dial peer above to prevent any SDP or media-related errors under the “Codecs” menu. Configure DID
  4. Select the voice URI you created from the previous step, from the popup window.
  5. Hit “Apply” and “Continue”, then finally, “Confirm.”
  6. All set! Now place a call to the number you are using for testing. It should reach your Ribbon SBC

Testing Calls

Any calls placed to the numbers associated with your URI are now delivered by Voxbone to the Ribbon SBC. If you used the {E164} keyword, your Ribbon SBC should see them as calls received to URI (called Voxbone DID)@YourEnvironment. You should be able to do a packet capture within the Ribbon SBC to capture the traffic and see the incoming call.

If you get any problems with setup here reach out to [email protected]

2. Setting Up Outbound Call Routing

For security reasons it’s important to look at number permissions and SIP digest headers when setting up outbound calling. These will allow you to use a number
for multiple applications.

But there are a few steps to take before we get there.

Enabling Outbound

Before you start, make sure you have an online account with Voxbone and that Voxbone’s service interoperates with your network by following the inbound guide above.

Then check the following:

  • That your Account Manager has activated Voxbone’s outbound service for your account, and for your country of choice
  • That you’ve got 2 test numbers for outbound calling. These are test numbers in countries that have our outbound service available. Our team will confirm that access has been granted for these numbers.
  • If the country you are using requires Emergency Services enabled, please ensure you speak to our team about getting this set up at the same time, as otherwise it might delay this process.

Go to ‘Configure DIDs’ in the Voxbone platform, and select the numbers you wish to set up for outbound service. Click on ‘VoxOut National’ and click to enable, and then be sure to hit ‘Apply’ to update the configuration.

Voxbone Voice URI - Ribbon SBC

This allows you to use this number as an outbound presentation number across any number of integrations.

Enabling SIP Digest Security

The next thing that needs to be set up is the security configuration that Voxbone requires for outbound calling. Voxbone uses SIP Digest headers. To set up the credentials, please go to ‘Configure Outbound Voice’.

Here you can add the username and password used on the system.

Voxbone configure - Ribbon SBC

Note: We strongly recommend you use the generation tool to generate a large, complex key for use within the system. This is a central configuration and only needs setting up once.

Setting Up Call Diversion

To allow call forwarding or call diversion to support passing or presenting third-party call IDs, the system needs to have the following setup.

  • The number listed in the ‘FROM’ field can be either a Voxbone or third-party number
  • The number in the ‘TO’ field can be a number listed in our routing prefix table
  • The number in the ‘DIVERSION’ field must be a Voxbone number activated for outbound voice

Your Ribbon SBC Settings

To support Outbound you may need to ensure you have firewall rules enabled here too based on your security approach.

From: RibbonSBC To: {Voxbone}  Ports {5060,5061} Protocol:UDP

From: RibbonSBC To: {Voxbone}  Ports {5060,5061} Protocol:TCP

From: RibbonSBC To: {Voxbone}  Ports {10000,24000} Protocol:UDP

Once the firewall is in place, you need to setup your SIP configuration to forward the Voxbone Outbound location (, or This single configuration is “route optimised” so it will then direct you into the relevant superPoP to give you the best latency and voice quality.

Please note that we expect requests to be made in the format of the From being [email protected] so this will require number translations if your system is not dealing with the numbers in +E164 format.

It’s within the SIP Server Tables you are configuring this capability. Please note the screenshot uses an old configuration. Please use or

Ribbon SBC

Finally the username and password setup in the Outbound Calling Configuration goes into the remote Authorization Table as below.

Create remote Authorization Entry - Ribbon SBC

For any questions, please contact us