Microsoft Teams Direct Routing: The Complete Guide  

2. How does Microsoft Teams Direct Routing work? 

Direct Routing establishes a bridge between the Teams cloud and traditional telephony using a certified SBC. In a typical deployment: 

• Outgoing calls: Teams → SBC → PBX/PSTN
• Incoming calls: PSTN/PBX → SBC → Teams

The SBC acts as a secure gateway, handling signaling and media between Teams and the PSTN. You can connect almost any PSTN trunk to Teams and interoperate with thirdparty equipment such as PBXs or analog devices. Because the SBC sits at the edge of your network, you maintain existing numbers and carrier contracts while migrating voice services to the cloud. 

3. What do you need for Direct Routing? 

Microsoft’s guidance lists several infrastructure and licensing prerequisites for Direct Routing: 

• Supported SBC – You must use a certified SBC.
• Telephony trunks – At least one telephony trunk or thirdparty PBX must connect to the SBC.
• Microsoft 365 tenancy – Users must be homed in Microsoft 365.
• Domains and FQDN – You need one or more registered domains (not the default *.onmicrosoft.com domain) and a fully qualified domain name for the SBC.
• Public IP and DNS – The SBC requires a public IP, a DNS entry pointing to that IP, and a publicly trusted certificate.
• Connection points – The SBC connects to Microsoft’s PSTN hub via three FQDNs: sip.pstnhub.microsoft.com, sip2.pstnhub.microsoft.com and sip3.pstnhub.microsoft.com.
• Licensing – Each user needs a Teams Phone license in addition to the Microsoft Teams license. An Audio Conferencing license is required for dialin meetings. 

4. How do I set up Direct Routing? 

Implementing Direct Routing involves several stages. At a high level: 

1. Decide on your SBC strategy – Choose whether to deploy your own SBC or work with a managed provider. 
2. Prepare the network – Ensure you have a public IP, DNS entry, certificate and registered domains.
3. Deploy and configure the SBC – Install the SBC (physical or virtual), connect it to your telephony trunks and configure SIP signaling to Teams.
4. Register the SBC with Teams – Create voice routing policies and assign them to users through the Teams Admin Center or PowerShell.
5. Port and assign numbers – Move existing phone numbers to your chosen carrier and assign them to users.
6. Test and go live – Validate call flows and quality before rolling out to all users. 

Because Direct Routing touches network, telephony and Microsoft 365, organizations often engage experienced partners. Deployment can take a few weeks, especially in multi-country scenarios. 

5. How much does Microsoft Teams Direct Routing cost?

There is no standard price for Direct Routing. Costs vary by provider and depend on factors such as the number of users, whether you bring your own SIP carrier, and whether call minutes are bundled. In general, you will pay for: 

• Teams Phone licenses for each user. 
• Rental of telephone numbers and call paths (which may be bundled with call minutes). 
• Additional call charges if you exceed any included minutes.
• Professional services or managed SBC fees when a partner handles configuration and ongoing management. 

Different providers offer per user pricing or consumption based models. Evaluate each offer carefully to understand all components of your monthly bill. 

6. How do I choose a Direct Routing provider or partner? 

There is no official “Direct Routing provider”; the only Microsoft certified element is the SBC. You can host your own SBC or work with a telecom provider who manages the infrastructure. When evaluating partners, consider: 

• Global reach – Ensure the provider can support all the countries where you need PSTN connectivity.
• SLA and support – Look at uptime guarantees, support hours and escalation paths.
• Number porting expertise – Confirm that they can handle complex number porting and migration scenarios.
• Managed services – Decide whether you want a managed SBC service or will manage the SBC yourself; managed services reduce operational overhead but may cost more. 
• Hybrid flexibility – Choose a partner who can help you mix Direct Routing and Operator Connect, so you can use the right model for each region or use case. 

A thorough assessment of providers’ security, compliance and integration capabilities is essential before signing a contract.

7. How does Direct Routing compare with other PSTN options? 

Microsoft offers three primary ways to connect Teams Phone to the PSTN: 

• Direct Routing – You connect your own or a partner’s SBC to Teams. This offers maximum control, supports complex call flows, and integrates with legacy systems. Deployment takes longer and requires specialized skills.
• Operator Connect – You select a certified operator via the Teams Admin Center. The operator manages the connection, phone numbers and PSTN services. This is faster to deploy and centrally managed but offers less routing flexibility. 
• Calling Plan – Microsoft acts as the carrier. This option is easy to set up but is limited in geographic reach and feature customization.

8. What are the advantages of Direct Routing? 

Direct Routing offers several important benefits: 

1. Flexibility and choice – It allows connection to almost any PSTN trunk and lets you choose or retain your preferred carrier. You can create custom call flows and policies tailored to your organization’s needs.
2. Cost efficiency – You pay only for the services you need and can leverage existing telephony investments, shifting costs from capital expenditure to operational expenditure. Consolidating carriers for international calls can reduce long distance charges.
3. Standardization and simplification – Direct Routing standardizes communication on a single platform. You can port existing numbers and reduce the number of vendors you manage. 
4. Hybrid work support – Employees can use their business numbers from anywhere, even in countries where Operator Connect isn’t available. Direct Routing is ideal for integrating analog devices, elevators and paging systems.
5. Advanced features – A Direct Routing provider can offer call recording, auto attendants, contact center integration and compliance features beyond what Calling Plans provide. 

9. What are the drawbacks or considerations? 

While powerful, Direct Routing is not a fit for every organization: 

• Complexity – Deploying and managing an SBC requires expertise in networking, telephony and Microsoft 365. 
• Infrastructure costs – Hosting your own SBC or paying for a managed SBC service can increase costs compared to Operator Connect or Calling Plans. 
• Longer deployment timeline – A simple cloud SBC setup can take two to three weeks; complex, multi-country deployments take longer. 
• Ongoing management – You need to monitor call quality, maintain certificates and update routing policies; smaller organizations may not have the resources for this. 

In many cases, organizations prefer to work with a voice provider for Direct Routing. 

10. Is Direct Routing right for your business?

Direct Routing is ideal when you need maximum control over call routing, must integrate legacy telephony systems or analog devices, or require coverage in countries where Microsoft or its operators don’t offer PSTN replacement. It also suits organizations that wish to retain existing carriers, negotiate better rates or create bespoke call flows. 

You don’t have to choose just one option. Many mid-to-large enterprises use Operator Connect for core, high volume countries and Direct Routing for edge cases like complex call flows or regions with regulatory constraints. By mixing both models, you can balance speed, flexibility and cost. 

If your needs are simple and you only require basic calling in a few countries, Microsoft Calling Plan may suffice. For more complex environments, Direct Routing - either alone or combined with Operator Connect - delivers the flexibility and control required for a modern, global communications strategy. 

Need help deciding? Our team specializes in Teams Phone deployments. Whether you’re evaluating Direct Routing, Operator Connect or a hybrid approach, we can guide you through planning, implementation and support.

👉 Reach out for a free consultation to determine the right mix for your organization.