Best Practice - Configure Direct Routing Survivable Branch Appliance (SBA)

Overview

The Direct Routing Survivable Branch Appliance (SBA) is a Ribbon Communications SBC 1000/2000 offer accomplished through close cooperation with Microsoft®. The SBA allows Direct Routing telephony services to remain available to Teams clients during a connectivity outage with Microsoft® 365 Phone System.

SBC 1000/2000 Direct Routing SBA offers Direct Routing call services to Teams clients

Direct Routing SBA - Quick Facts

Prerequisites

Direct Routing

• The Direct Routing SBA must have access to Azure AD, which must be created and enabled on Azure before SBA deployment.
  

  Note

  You must have an Application (client) ID (appId) and an Application Secret (secret) from the Microsoft Azure portal to complete the deployment.

   

• The Microsoft Teams Tenant should be configured for Direct Routing. Refer to https://docs.microsoft.com/en-us/microsoftteams/direct-routing-configure for more information;

• The Microsoft Teams Tenant should be configured for Direct Routing SBA. Refer to: https://docs.microsoft.com/en-us/microsoftteams/direct-routing-landing-page.
  

• Direct Routing SBA requires an Internet link to connect the Teams tenant.

Direct Routing SBA (capable of SBC 1000 or SBC 2000)

Hardware and License

Please confirm: 

• Licenses for the following features must be activated before deployment: 

  • SIP sessions

  • Direct Routing SBA

• SBC and SBC Communication service must be on Ribbon SBC Edge Portfolio Release 9.0.1.

• Confirm that your ASM features a licensed Windows Server 2019 or 2012R2 License copy.
  

  Note

  Ribbon recommends upgrading the ASM to Windows Server 2019, which has a few benefits: it is still supported by Microsoft and will get vulnerability fixes. Microsoft ended general support for Windows Server 2012R2 and it may not provide fixes to vulnerabilities.

   

• Confirm that your ASM is loaded with the Office 365 Direct Routing SBA image.
  
  Example of the Windows License and Office 365 Direct Routing SBA Image Type
  
  
  

Name Resolution

• Public or Private FQDN that point Direct Routing SBA IP. No Public IP is required for the Direct Routing SBA.

• Direct Routing SBA should resolve SBC Public FQDN with an address it can access; this is completed automatically for the SBC that hosts the ASM.

Encryption-Related Certificates

Microsoft requires an SHA256 certificate for Direct Routing SBA in order to establish a TLS connection with SBC. There are several options:

• Shared SBC Public certificate (recommended). This is only possible if your SBC certificate is matching one of the following 2 options:

  • SBC Certificate is a Wildcard certificate

    • i.e., SBC Certificate Common Name "CN: *.mydomain.com" or SBC Certificate Subject Alternative Name "SAN: *.mydomain.com".

  • SBC Certificate has a SAN for Direct Routing SBA

    • i.e., SBC Certificate Common Name "CN: sbc.mydomain.com" and SBC Certificate Subject Alternative Name "SAN: sba.mydomain.com."

• Use an existing Public or Private Certificate that covers Direct Routing SBA FQDN.

• Create a new Public or Private Certificate that covers Direct Routing SBA FQDN. In this case, a Public or Private Certificate Authority must be ready to sign the certificate for Direct Routing SBA.

• When using a private certificate for the SBA, please ensure that it meets these requirements:

  • The CN (Common Name or Subject) must contain the SBA FQDN.

  • The SAN (Subject Alternative Name) must also contain the SBA FQDN.

Firewall Protocols and Ports

Microsoft requires the following ports to be open on the firewall for the SBA server to communicate with the Teams client, the SBC, the NTP server, or Microsoft 365:

• Port 443
• Port 3443 
• Port 4444 
• Port 5061 
• Port 8443 
• UDP Port 123
• SRTP/UDP Port 5000 or higher
• SRTP/UDP Port 16384 or higher
• The firewall must also allow ICMP requests from the SBA to Microsoft, and ICMP replies from Microsoft to the SBA.

The following table provides information on the ports and the associated devices. 

Firewall Ports and Associated Devices

¹ This port range is based on the settings of your SBC in Settings > Media > Media System Configuration > Port Range.

For more information on the firewall ports, refer to: https://learn.microsoft.com/en-us/microsoftteams/direct-routing-survivable-branch-appliance.

For more information on Azure IP Range and Service, refer to: https://www.microsoft.com/en-us/download/details.aspx?id=56519.

For information on troubleshooting the Direct Routing SBA, refer to Troubleshooting Direct Routing Survivable Branch Appliance.

Step 1: Configure SBC 1000/SBC 2000

Run Easy Configuration Wizard

Follow the instructions for your specific scenario; both are listed below:

• SCENARIO 1: If your SBC is not yet configured to connected Direct Routing (Greenfield), follow this section: SBC is not yet configured to configured to connected Direct Routing (Greenfield)

• SCENARIO 2: If your SBC is already configured to connected Direct Routing (Upgrade from Standalone Direct Routing), follow this section: SBC is already configured to connected Direct Routing (Upgrade from Standalone Direct Routing).

SBC Not Configured for Direct Routing ("Greenfield")

OPTION 1: To connect Direct Routing with a SIP Trunk, refer to Configure SIP Trunk with Microsoft Teams.

• In Step 2, set Configure Direct Routing SBA as True and enter the Direct Routing SBA FQDN.

OPTION 2: To connect Direct Routing with an ISDN PSTN, refer to Configure ISDN PSTN with Microsoft Teams.

• In Step 2, set Configure Direct Routing SBA as True and enter the Direct Routing SBA FQDN.

  

SBC Already Connected to Direct Routing (Upgrade from Standalone Direct Routing)

1. Follow the steps on this page: Configure Single Leg Endpoint for Microsoft Teams. In Step 2, configure Configure Direct Routing SBA as True and enter the Direct Routing SBA FQDN.

2. Remap the call routing Direct Routing SBA Signaling Group:
   

   1. In the WebUI, click the Settings tab.

   2. From the left navigation pane, under Signaling Groups, select the Office 365 Direct Routing SBA SIP Signaling Group.

   3. Modify the Call Routing Table to select the Microsoft Teams Direct Routing call routing table previously used on your device.

      

3. Enable Forking to Direct Routing Server:
   

   1. From the left navigation pane, select  Call Routing > Call Routing Table. Select the From SIP Trunk call routing table.

   2. Select the existing entry with First Signaling Group set to Teams Direct Routing.

   3. Set the Fork Call to Yes.

   4. Click Apply.

      

4. Add a call route entry for Direct Routing SBA:
   

   1. From the left navigation page, select Call Routing > Call Routing Table.

   2. Select From the SIP Trunk table.

   3. Click the ().

   4. Configure the parameters as shown below. Leave all other parameters as default.

   5. Click OK.

      Parameter	Value
      Description	To Office 365 Direct Routing SBA
      Number/Name Transformation Table	From SIP Trunk: Passthrough
      Destination Signaling Groups	Office 365 Direct Routing SBA

      

5. Delete unused resources:
   

   1. From the left navigation pane, select Signaling Groups.

   2. Delete the SIP Signaling Group called Teams Direct Routing that the last Easy Config Wizard has created.

      Signaling Group Accuracy

      If you receive an error that a route entry uses this resource, you may have attempted to delete the wrong Signaling Group.

      

   3. From the left panel, select Call Routing > Call Routing Table and delete the Call Routing Table From Microsoft Teams Direct Routing created by the most recent use of the Easy Configuration Wizard.

      SIP Signaling Group Error

      If you receive an error that the SIP_SG entry is using this resource, you may have attempted to delete the wrong Call Routing Table.

      

      Migration from Lync 2013 SBA/Skype for Business 2015 SBA to Office 365 Direct Routing

      After creating the new configuration, update the existing routing table to fork the call between the Signaling Group Direct Routing and Direct Routing SBA instead of Skype for Business.

Step 2: Configure Sharing Trusted Certificate Authority Information

The Trusted Certificate Authority information associated with the SBC and the Direct Routing SBA must be shared within the platform.

Export the SBC's Certificate Authority Information to the Direct Routing SBA:

1. In the WebUI, click the Tasks tab.

2. Under the SBC Easy Setup, select Certificates.

3. Select the certificate from the Trusted CAs tab and click Export Trusted CA Certificate.

4. Save the file on your PC. Repeat steps 3 and 4 for each CA certificate in the table. (These are the SBC CA Certificate used later per Import SBC CA in Direct Routing SBA.)

Import the Direct Routing SBA's Certificate Authority Information to the SBC:

1. Export the Root and Intermediate Certificate of the Certificate Authority (Public or Private) that as/will generate the Direct Routing SBA certificate.

2. In the WebUI, click the Tasks tab.

3. Under SBC Easy Setup, select Certificates.

4. From the Trusted CAs tab, select Import Trusted CA Certificate.

5. Select the correct format (Copy and Paste or File Upload) and click OK. Repeat steps 4 and 5 for each CA certificate.

Step 3: Re-initialize the ASM on the Teams SBA Image

Re-initializing the ASM on the Teams SBA Image restores the ASM to an unconfigured state. Follow the steps in Re-initializing the ASM and return to Step 4. 

Step 4: Install SBC COMMs

To ensure the SBC 1000/2000 can communicate with the ASM, install the latest SBC Communication Service. Following the steps in Upgrading the SBC Communication Service Version , return to Step 5. 

Step 5: Setup the Office 365 Direct Routing SBA

Setting up the Office 365 Direct Routing SBA consists of four steps. See below for each step.

• ASM Configuration
• Generate CSR 
• Manage Certificates
• Configure Office 365 Direct Routing SBA

Configure ASM for Direct Routing SBA

1. Login to the WebUI of the SBC Edge Portfolio.

2. Navigate to Tasks > Office 365 Direct Routing SBA > Setup.

3. Click the ASM Config tab and configure/verify your ASM's network and IP settings.

   1. From the Remote Desktop Enabled drop-down list, select Yes (to enable Remote Desktop) or No (to disable Remote Desktop). The recommended setting is No).

   2. From the Windows Firewall Enabled drop-down list, select Yes (to enable Windows Firewall) or No (to disable Windows Firewall). The recommended setting is Yes).

   3. From the Proxy Enabled drop-down list, select Yes (enables use of the Proxy Server on the ASM) or No (disables Proxy Server).

   4. Configure/verify the Network and IP settings of your ASM.

4. Click Apply.

   

Generate CSR

1. Login to the WebUI of the SBC Edge Portfolio.

2. Navigate to Tasks > Office 365 Direct Routing SBA > Setup.

3. Click the Generate CSR tab.

4. Generate the CSR as shown below. To ensure that a valid CSR is created for Direct Routing SBA usage, see the certificate requirements.

5. Copy the CSR from the lower pane of the Generate CSR page and save it as a .txt file.

After the Certificate Authority signs the CSR, you receive the PKCS7 Certificate file.

Manage Certificates

Import SBC CA in Direct Routing SBA

1. Login to the WebUI of the SBC Edge Portfolio.

2. Navigate to Tasks > Office 365 Direct Routing SBA > Setup.

3. Click the Manage Certificate tab.

4. Click the Action drop-down list and select Import X.509 Signed Certificate.

5. Paste the SBC CA certificate in the window and click OK.

Import Direct Routing SBA Certificate

1. Login to the WebUI of the SBC Edge Portfolio.

2. Navigate to Tasks > Office 365 Direct Routing SBA > Setup.

3. Click the Manage Certificate tab.

4. Click the Action drop-down list and select one of the following options:

   • Import X.509 Signed Certificate. This option is used if you generate a Certificate Request (CSR), which is the initial deployment. Paste the certificate in the window and click OK.

   • Import PKCS12 Certificate and Key. This option imports a certificate you created. Enter the password, select the file (certificate) to import, and click OK.

5. Proceed with the next step.

Configure Office 365 Direct Routing SBA

1. Login to the WebUI of the SBC Edge Portfolio.

2. Navigate to Tasks > Office 365 Direct Routing SBA > Setup.

3. Click the Configure Office 365 Direct Routing SBA tab.

4. Configure the information appropriately for your Direct Routing SBA:

   1. SBA FQDN. Must match the FQDN used to define this Direct Routing SBA in the Teams tenant item Teams Survivable Branch Appliance (New-CsTeamsSurvivableBranchAppliance).

   2. SBC FQDN. Must match the FQDN used to define the SBC that hosts this Direct Routing SBA in the Teams tenant item Online PSTN Gateway (New-CsOnlinePSTNGateway).

   3. Create Azure AD Application. Enables creating new Azure AD Application credentials for this Direct Routing SBA.

      • If you have already created Azure AD Application credentials, select No and enter the credentials in Application ID and Application Secret.

      • If you have not previously created the Azure AD Application credentials (or are unsure what this means), select Yes and enter the credentials in Azure Administrator Account Name and Azure Administrator Account Password.

        Azure Administrator Account Considerations

        This Azure Administrator Account account needs a Global Administrator, an Application Administrator, or a Cloud Application Administrator role.

   4. Enter a Teams Tenant ID. To locate this information, refer to https://docs.microsoft.com/en-us/onedrive/find-your-office-365-tenant-id.
      
      

5. Click Apply.

Step 6: Install Teams SBA Package for ASM

Install the Teams SBA latest package, ASM_Teams_xxxx-xx-xx.pkg (e.g., ASM_Teams_2021-01-18.pkg). Follow the instructions for Installing an ASM Package.

Step 7: Configure Deployments with Additional SBCs (if required)

1. Enable Remote Desktop on the ASM. Refer to:  Enabling and Disabling Remote Desktop on the ASM.

2. Connect the ASM using Remote Desktop Protocol.

3. As an administrator, open the file C:\Windows\System32\drivers\etc\hosts

4. Add an entry for all the SBCs on the same Branch Office. The entry must contain the SBC Public FQDN and the Private IP Direct Routing SBA uses to reach this SBC.

   

5. Save and close the file.

Step 8: Test the Direct Routing SBA

Complete the following steps to confirm the configuration.

Import Direct Routing SBA Certificate Authority

1. Navigate to Tasks > Office 365 Direct Routing SBA > Certificate.

2. Ensure the Certificate Chain is reported as valid.

   • If the page reports Missing Root or Intermediate CA, return to the Setup / Manage Certificate tab, select Import X.509 Signed Certificate and import all the root and trusted certificates that generate the Certificate of the Direct Routing SBA. Once completed, return to the  Certificate tab and ensure the Certificate Chain is reported as valid.

     

Confirm SBA Status

1. Login to the WebUI of the SBC Edge Portfolio.

2. Navigate to Tasks > Application Solution Module > Operational Status.

3. Confirm the Office 365 Direct Routing SBA Service:

   • Service Status is reported as Running

   • Service Information is reported as ready

     

Confirm SIP Option

The signaling groups configured for the Microsoft Teams Direct Routing SBA include counters for SIP request and response messages related to incoming and outgoing options. As the SBC 1000/2000 operates with Microsoft Teams Direct Routing SBA, the message counters show increasing numbers. Ensure the message counts and investigate potential sources of related integration issues as follows:

1. In the WebUI, click the Settings tab.

2. In the left navigation pane, click Signaling Groups.

3. From the signaling group configured for Microsoft Teams Direct Routing SBA, click Counters.

4. Check for an increasing message count in Outgoing Options.

5. Check for an increasing message count in Incoming 2xx. 

   1. If not, Ensure the Sip Server Entry for the Direct Routing SBA matches the cases of the Certificate CN or SAN used by the Direct Routing SBA.

   2. If you just completed the deployment of SBA, a restart of the SBA service may be required before you see the 200 OK increasing message count.

6. Check for an increasing message count in Incoming Options.
   

7. Check the message count in Outgoing 2xx. If the number increases, the changes you made during validation have resolved the integration issue(s).
   

   

Confirm Teams Client Connection to SBA

1. Login to the WebUI of the SBC Edge Portfolio.

2. Navigate to Tasks > Office 365™ Direct Routing SBA >Teams Client Connected.

3. Confirm that your Teams client is reported.

   

Confirm Teams Client Can Run in Offline Mode

1. Remove the Internet link between the Branch Office and the Microsoft Teams cloud.

2. Open the Teams client. A banner is displayed, which indicates that the Teams client will ONLY use the SBA to make/receive calls when offline.

   

Step 9: Place Test Call

Complete the following steps to place a test call:

1. In the WebUI, click the Diagnostics tab.

2. In the left navigation pane, click Test a Call.  

   

3. Configure the parameters for test calls as follows:

   Parameter	Value
   Destination Number	Type a telephone number assigned to a Teams user.
   Origination/Calling Number	Type a telephone number assigned to a Local (SIP Trunk or PSTN) user.
   Call Routing Table	Select the routing table that handles the calls from Local resources (From PSTN or SIP Trunk).

4. Click OK; the call should ring the Teams Client.

   

5. If the test call does not ring, the Teams client: 

   1. Check that the SBC IP routing is configured correctly.

   2. Check whether you can place a call from Teams to the SBC. 

   3. If the call does not reach the SBC, then complete the following:

      1. Confirm that the firewall is configured correctly to allow incoming SIP TLS messages.

      2. Confirm that the federated IP addresses are correctly configured.

      3. If the call is Anonymous, refer to  Configuring SBC Edge for Select Microsoft Teams Direct Routing Related Migration Scenarios for more details.

      4. If the call from the SBC to Teams does not connect due to a SIP 488 "Not Acceptable Here" coming from Teams with the reason "IceCandidatesAbsent," disable Media Bypass on Teams or enable ICE Lite on the SBC. For details, refer to Configuring SBC Edge for Select Microsoft Teams Direct Routing Related Migration Scenarios.

Step 10: Access Logs

1. Login to the WebUI of the SBC Edge Portfolio.

2. Navigate to Diagnostics> Teams Direct Routing > SBA logs.
   

3. .
   

   

4. Use the table on the same page to view or Download the Direct Routing SBA log files.

   

Step 11: Restart Services

1. Login to the WebUI of the SBC Edge Portfolio.

2. Navigate to Tasks > Office 365 Direct Routing SBA > Start/stop Services.
   

3. Select Stop Service in Teams Server as the Service Name from the Service Action drop-down list, and click OK.

4. Wait for the action to complete.

5. From the Service Action drop-down list, select Start Service; in Service Name, select Teams Server, and click OK.

6. Wait for the action to succeed.