Microsoft Teams Hybrid Setup Guide: Architecture, Requirements, and Limitations
Microsoft Teams Hybrid is a deployment model where Microsoft Teams cloud services are integrated with on-premises infrastructure such as Active Directory, PBX systems, and Session Border Controllers (SBC). This approach allows organizations to gradually migrate from legacy telephony systems to Microsoft Teams while maintaining business continuity.
What is Microsoft Teams Hybrid?
Microsoft Teams Hybrid is a configuration where cloud-based Microsoft Teams works together with on-premises voice and identity systems. In this setup, users can use Microsoft Teams for meetings and collaboration while PSTN calling is handled through an on-premises SBC or PBX using Direct Routing.
How Microsoft Teams Hybrid Works
The call flow in a Teams Hybrid environment follows this path:
- Outbound calls: Teams client → Microsoft Teams cloud → Microsoft SIP Proxy → On-premises SBC → PSTN or PBX
- Inbound calls: PSTN → On-premises SBC → Microsoft SIP Proxy → Teams user
Types of Hybrid in Microsoft Teams
Identity Hybrid
On-premises Active Directory is synchronized with Azure Active Directory using Azure AD Connect. This enables single sign-on and centralized identity management.
Voice Hybrid
Voice Hybrid is achieved using Microsoft Teams Direct Routing. A certified SBC connects Microsoft Teams to an on-premises PSTN or PBX system.
Skype for Business Hybrid
Organizations using Skype for Business can run a hybrid mode where users are hosted in both Skype and Teams during migration.
Microsoft Teams Hybrid Requirements
Licensing
- Microsoft 365 E3 or E5
- Microsoft Teams Phone license
- Audio Conferencing (optional)
Infrastructure
- Certified SBC (AudioCodes, Ribbon, Oracle)
- Public IP address for SBC
- Public trusted SSL certificate
- Firewall with required ports open
Network Ports
- TCP 5061 for SIP TLS
- UDP 49152–53247 for media
- TCP 443 for HTTPS
DNS and Certificates
- Public DNS record for SBC (example: sbc.company.com)
- Certificate issued by trusted CA such as DigiCert or GoDaddy
Information Required Before Setup
- Microsoft 365 tenant name and domain
- SBC FQDN and public IP
- PSTN DID ranges
- User UPN and phone numbers
- Country and emergency location details
High-Level Setup Steps
- Configure Azure AD Connect for identity synchronization.
- Install and configure certificate on SBC.
- Connect SBC to Microsoft Teams using PowerShell.
- Create voice routes and routing policies.
- Assign phone numbers and policies to users.
- Test inbound and outbound calling.
Limitations of Microsoft Teams Hybrid
- Fax and analog devices require ATA gateways.
- Emergency calling needs extra configuration.
- Some PBX features are not supported.
- Internet dependency for call signaling.
- SBC becomes a single point of failure without high availability.
Security Considerations
- Use TLS and SRTP for encrypted calls.
- Enable firewall and IP filtering.
- Keep certificates valid and updated.
- Enable monitoring and logging.
When Should You Use Microsoft Teams Hybrid?
Microsoft Teams Hybrid is best suited for organizations that already have on-premises PBX systems and want to migrate gradually to Microsoft Teams while keeping control over PSTN connectivity and compliance.
Conclusion
Microsoft Teams Hybrid provides flexibility by combining cloud collaboration with on-premises telephony. With proper planning, certified SBC hardware, and correct licensing, organizations can achieve a stable and secure hybrid deployment.
Frequently Asked Questions (FAQ)
Is Microsoft Teams Hybrid still supported?
Yes, Microsoft Teams Hybrid is supported using Direct Routing and hybrid identity configurations.
Can Microsoft Teams Hybrid work with existing PBX?
Yes, Teams Hybrid can integrate with Cisco, Avaya, and other PBX systems using a certified SBC.
What is the main advantage of Teams Hybrid?
The main advantage is gradual migration without disrupting business operations.
