Teams On-network Audio Conferencing

Hi All,

a new recent feature called On-network Audio Conferencing allow to integrate Teams Meeting Audio Conferencing Service with Teams Direct Routing.

This new feature break an historical barrier between the Teams Meeting and Teams PSTN Calls: both modes with their own licenses, they never interacted in the past.

On-network Audio Conferencing will enable your SBCs to communicate with Microsoft Teams Audio Conferencing Service:

  1. Placing Dial In calls from yours SBC to Audio Conferencing
  2. Receiveing Dial Out calls from Audio Conferencing to your SBCs

Quoting the official documentation

"On-network Conferencing allows organizations to send inbound and outbound Audio Conferencing calls to Microsoft dial-in numbers through Direct Routing. This capability is not intended to extend the support of Audio Conferencing to third party dial-in numbers. On-network Conferencing is not supported if it is used to route inbound calls to the Audio Conferencing service through third party dial-in phone numbers."


There are only few prerequisites to enable On-network Audio Conferencing:

  1. Assign Audio Conferencing licenses (you cannot use Pay-per-Minute license) to the users that schedule the Teams Meeting.
  2. Direct Routing is correctly configured
  3. You have a Session Border Controller (SBC) configured for Direct Routing.

Meeting Dial-In calls setup

With On-network Audio Conf is now possible to directly route calls from internal PBX extensions to Audio Conf numbers, without going on PSTN (reducing costs).
It’s also possible to route PSTN inbound calls to Audio Conf numbers, but it’s not supported.

Assuming you have a correctly working SBC configured for Teams Direct Routing, it’s quite easy to setup this new service.

The first and only information you will need is your Default Conference Bridge Number.
To obtain it open the Teams Admin Center -> Meeting -> Conference bridges, search for your Default Phone number and take it.
In the example below the Default number is the bridge in Milan (Italy)

On your SBC add a simple rule that intercept calls to MS Audio Conf numbers and route them to Direct Routing instead of PSTN

You can also route PSTN inbound calls to Audio Conf numbers, but it’s not supported

On your SBC add a very simple rule that transform yours Audio Conf numbers to the MS conference bridge number you get before

Then route these calls to Teams via Direct Routing

Meeting Dial-Out calls setup

Meeting Dial-Out calls are calls that starts from a Meeting to PSTN numbers, like landlines and mobile numbers, including call-me-at calls.

This new feature come with a new Online User Policy called OnlineAudioConferencingRoutingPolicy

The policy is used for the routing of dial-out calls from Teams meetings via Direct Routing, and it is equivalent to the CsOnlineVoiceRoutingPolicy for standard PSTN calls via Direct Routing.
This policy need to be created and assigned to every users that need to place meeting Dial-Out calls.

With the new policy came new cmdlets:

  • New-CsOnlineAudioConferencingRoutingPolicy
  • Set-CsOnlineAudioConferencingRoutingPolicy
  • Get-CsOnlineAudioConferencingRoutingPolicy
  • Grant-CsOnlineAudioConferencingRoutingPolicy
  • Remove-CsOnlineAudioConferencingRoutingPolicy

Assuming you have Dial-Plan and Direct Routing up and running, configuration steps are:

  1. Create a dedicated PSTN Usage
  2. Configuration of OnlineAudioConferencingRoutingPolicy
  3. Assign policy to users
  4. SBC configuration
If you do not have Direct Routing configured yet, check the MS Docs guide here:

Create a dedicated PSTN Usage

Even if you have your configured Teams Direct Routing setup, I suggest to create a dedicated PSTN Usage to route Audio Conf outbound calls.

When a dial-out call is initiated from the meeting, voice routes will be used to determine the routing of the call based on the PSTN
usages that are associated to the Organizer User via the user’s voice routing policy

So for example i want to route to the SBCs in Italy every meeting outbound calls to Internal Legacy PBX and to Italian destinations (so the called user will recognize the Corporate calling number), leaving every other meeting outbound calls to other Countries managed by Microsoft, so I created a new PSTN Usege and a new Voice Route

Set-CsOnlinePstnUsage -Identity Global -Usage @{Add="IT-AudioConfDirectVoip"}

New-CsOnlineVoiceRoute -Identity "IT-LegacyPBX" -NumberPattern "^\+390512345678" -OnlinePstnGatewayList, -Priority 1 -OnlinePstnUsages "IT-AudioConfDirectVoip"

New-CsOnlineVoiceRoute -Identity "IT-National" -NumberPattern "^\+39" -OnlinePstnGatewayList, -Priority 2 -OnlinePstnUsages "IT-AudioConfDirectVoip"

Configuration of OnlineAudioConferencingRoutingPolicy

Like in the 1:1 Teams calls with New-CsOnlineVoiceRoutingPolicy, we have to create a new Audio Conferencing Routing Policy with allowed PSTN Usage Policy that the users will use to route meeting outbound calls.

New-CsOnlineAudioConferencingRoutingPolicy "<PolicyName>" -OnlinePstnUsages "<PSTN Usage list>"

So for example we can create a new policy like this one that will use the previously created PSTN Usage Policy

New-CsOnlineAudioConferencingRoutingPolicy "IT-AudioConferencing" -OnlinePstnUsages "IT-AudioConfDirectVoip"

Assign policy to users

The last step is the more important, we have to assign the previously created OnlineAudioConferencingRoutingPolicy to every users that need to use these new feature.

Grant-CsOnlineAudioConferencingRoutingPolicy -Identity "<User
Identity>" -PolicyName "<OnlineAudioConferencingRoutingPolicy>”

So our example will be

Grant-CsOnlineAudioConferencingRoutingPolicy -Identity "" -PolicyName "IT-AudioConferencing”

SBC configuration

If the called number from the Meeting is a PBX extension, to you Legacy PBX for example, you do not need specific rules on the SBC

Instead, if the called number is a public PSTN number, you have to normalize the Caller ID, because the Caller ID of the calls (from Audio Conf Service to SBC) will be your Default Conference Bridge Number, it’s mandatory to have a Transform Rule that change the Caller ID to one of the DID number range owned.

PSTN minutes pool consumption and reports

I want to be sure that on-network dial out calls do not consume minutes from Audio Conferencing PSTN minutes pool (60 minutes for every Audio Conferencing assigned license).

So I’ve made some other test calls and the results are:

  1. no minutes charge is applied to on-network dial out calls (good!)
  2. if you go in the TAC -> Analytics & reports -> PSTN and SMS (preview) report -> Direct Routing you will find the call listed as dr_conf_out

That’s all.

I think it’s a great news and a very good improvement of the whole Teams system.
As always, I hope this could help some of you.

10 thoughts on “Teams On-network Audio Conferencing

Add yours

  1. Luca I use a Ribbon SBC like you but when it tries to turn around the calls to Teams for these numbers, Teams rejects the call with a 400 Bad Request and the reason is “Unable to parse RURI”

    Did you have to do something to your SBC config other that what is listed…seems like this may be a SIP REFER issue?


    1. I Jerry, for Dial-In calls you do not have to do nothing more than manipulate the called number, setting it to your Audio Conf Main number. It’s not a REFER transfer. Give me some more details on the call flow please, I’ll try to find the issue.


      1. Luca, thanks, I worked it out with it being a regex problem. I had to put parentheses around the input field value for SWELite to pass it as a proper URL when using /1 as the output field value. I remembered this after a previous issue.

        So this works great! Thank you for the detailed article as it is MUCH BETTER that what Microsoft provided.

        Liked by 1 person

  2. Both of these options still require each user creating meetings to have an audio conferencing license as well right?


  3. Thanks a lot Luca !

    I have been able to get it working with the condition that the organizer has an Audio Conferencing license.

    I have tried to do the same with On-Network and Direct Routing without Audio Conferencing (What companies could afford all required licenses ?) but unfortunately, it’s not working, since, without Audio Conferencing, the outgoing calls use the organizer’s voice routing. That would be so easy and convenient to have it also without Audio Conferencing…


    1. Hi Fabien,
      glad to help you. Unfortunately there is no way to avoid the expensive Audio Conf license if you want this kind of feature. In the near future there will be the option to choose a different carrier for Teams Audio Conference, but it’s not ready yet.
      Best. Luca


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