Teams Direct Routing - SFB to Teams Migration - User Phone Number Synchronization

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I am currently looking at the MS Direct Routing guidelines for enablement of users:

As part of this article, there is a sub section “Ensure that the user is homed online and phone number is not being synced from on-premises (applicable for Skype for Business Server Enterprise Voice enabled users being migrated to Teams Direct Routing)”

In this section, it states that a users ‘OnPremLineUriManuallySet’ parameter should be set to ‘True’ when checking via SFBO PowerShell session using the ‘Get-CsOnlineUser’ cmdlet.

If the result does come back as ‘False’ (which it is does when i migrate an EV enabled SFB test user) then the following cmdlet should be run via SFB on-premise management shell:

Set-CsUser -Identity "<User name>" -LineUri $null -EnterpriseVoiceEnabled $False -HostedVoiceMail $False

Following this then the user can be re-enabled via SFBO PS session with the associated phone number.


Up until now I have been preparing my customer environment for mass EV enabled user migration from SFB2015 on-premise to Teams and following the MS guidance from the following articles:

These articles cover the setup of SFB hybrid with attribute synchronization including the users phone number and then simply executing the ‘Move-CsUser’ cmdlet for ‘TeamsOnly’ mode to move users from on-premise to Teams.

With this approach it is my understanding that management of migrated users phone numbers should still be performed on-premise(and synched), and eventually once all users are migrated we can disable hybrid and decommission the SFB servers – covered in following article:


Can someone provide clarity on whether the synchronization for the phone number should be broken for SFB on-premise EV enabled users being migrated to Teams as the various current MS docs would not appear to be aligned and a bit confusing? This is important as I need to be clear in my migration plan for moving users from on-premise to Teams.



4 Replies

@paul schofield 


@Linus Cansby @Thorsten Pickhan one for you guys as I need to look after the boy tonight :D


Best, Chris

Hi @paul schofield and happy New Year!

From my point of view we are talking about two different things.

The first scenario, where you manage phone number OnPrem and let them synchronize to Azure AD and SFBO/Teams is Skype for  Business Hybrid Voice. In this scenario the Office 365 platform route all outbound PSTN calls to the OnPrem environment. The SfB Server OnPrem check the PSTN usage records etc. and routes the call to a defined PSTN Gateway which is connected to OnPrem environment. For inbound calls, the call is routed from the PSTN Gateway to the OnPrem SfB Server. The server makes a lookup where the is user is located. In case of an online user, the call is routed to Office 365. As far as I know, this scenario is not recommended or even supported by Microsoft for Teams Only user, but it works because there is still the SfBO backend as middleware in place.


In the second scenario we are talking about Teams Direct Routing. In this scenario the gateway is connected directly to the Office 365 platform. Calls are routed to and from Teams directly to and from the gateway or SBC.

Therefor if you plan to decommission the OnPrem SfB environment to a give date, I suggest implementing Teams Direct Routing in parallel to your SfB trunk. Build a second trunk from your gateway or SBC to Microsoft Teams and build routing rules for inbound and outbound calls. For the migration of SfB users to Teams I would follow the Teams Direct Routing guide from Microsoft, as you mentioned. Disable EV feature OnPrem, synchronize the change to Office 365 and enable the user for Teams Direct Routing.

BTW: Microsoft will retire the SfB Cloud Connector Edition on 31th of July 2021. Because Hybrid Voice is using the same PSTN routing mechanism, I guess this won't work after 31th of July anymore.

Hi @Thorsten Pickhan --- Happy New Year to you also.

Thankyou for your reply.

I already have my environment set up for Direct Routing with certified SBC's and associated trunks and routing rules - all is good and ready.

My query was really more for the user migration from SFB on-premise to Teams as with this and other previous deployments i have followed the MS guidelines to set up SFB hybrid/AAD connect so SFB on-premise attributes can synch with online - with this scenario any phone number admin would be done on-premise (msRTCSIP) but now MS tell us for Direct Routing users to affectively break the synch for the phone number - looking at their article, the only way to set the 'OnPremLineUriManuallySet' from false to true is to disable EV for the user on-premise and then wait for synch to take place for enabling on-line. Not ideal when we are dealing with bulk migrations as a process.



Hi @paul schofield , yes, this is my understanding. 

Of course you can force Azure AD to sync after made some changes OnPrem:

PowerShell Basics: How to Force AzureAD Connect to Sync (