Microsoft Teams Direct Routing
Use Microsoft Teams to make and receive business calls by securely connecting Teams Phone to a telecom provider through a Microsoft-certified Ribbon Session Border Controller.
Getting connected
Four requirements for calling from Teams
Direct Routing brings Microsoft 365, a telecom carrier, a certified SBC, and deployment expertise together in one calling architecture.
01
Teams Phone licensing
Each user needs an appropriate Teams Phone license in Microsoft 365. It is commonly included with E5 and can be added to eligible E3 or E1 plans, subject to the terms of your Microsoft agreement.
02
SIP trunk provider
A telecom provider offering IP phone lines (SIP trunks) for Microsoft Direct Routing. Organizations may retain a suitable provider or select a new one.
03
Microsoft-certified SBC
A certified Session Border Controller terminates the SIP trunks and acts as the secure interoperability bridge between Teams and the telephone network.
04
Deployment expertise
A trained team member or IT professional is required to configure, validate, document, and support the Direct Routing solution.
Reference architecture
How Direct Routing connects your calls
The certified SBC sits between Microsoft Teams and the PSTN service provider, securing and normalizing the voice connection.
Callers & PSTN
SIP Trunks
Ribbon SBC
Microsoft 365
Teams Users
Telephone network ↔ SIP trunks ↔ Microsoft-certified Ribbon SBC ↔ Microsoft 365 ↔ Teams users
The SBC’s role
More than a simple SIP connection
A properly configured SBC becomes the security, interoperability, migration, and resiliency layer between Microsoft Teams and the telephone network.
Security
The SBC operates as a voice-aware firewall and encrypts traffic, protecting calls and helping prevent unauthorized access through the voice network.
Interoperability
SIP trunk providers are not identical. Ribbon SBCs can adjust signaling and media parameters so the carrier and Microsoft Teams work together.
Legacy connectivity
Hardware SBC options can retain suitable analog phones, elevator phones, door phones, and fax machines through FXS interfaces.
Phased migration
Legacy PBX and Teams environments can coexist during migration, including simultaneous ringing through SIP forking where appropriate.
Resiliency and failover
Options include WAN failover and Microsoft Survivable Branch Appliance support to maintain calling capabilities during disruptions.
Deployment choice
Hardware, virtualized software, or cloud
Select an SBC deployment model that fits your sites, hosting strategy, local connectivity, legacy interfaces, capacity, and business-continuity requirements.
Hardware
Premises-based appliances for local connectivity, physical interfaces, survivability, and legacy migration.
- FXO, FXS, T1/E1 options where required
- Local PSTN and WAN connectivity
- Microsoft SBA and redundant hardware options
Ribbon platform families
SBC 1000, Edge 8000, EdgeMarc, SBC 5400, SBC 7000
Virtualized software
Software SBC deployment on suitable standard hardware or within a data center.
- Useful for local PSTN connectivity
- Scalable high-availability architectures
- Microsoft SBA support on applicable designs
Ribbon platform families
SBC SWe, SBC SWe Edge
Cloud instance
Cloud SBC choices for cloud PSTN connectivity and rapidly provisioned environments.
- AWS and Azure deployment options
- Kubernetes orchestration options
- Scalable high-availability designs
Ribbon platform families
SBC CNe, SBC SWe, SBC SWe Edge
Final platform selection is based on current Microsoft certification, product availability, licensing, call capacity, hosting requirements, and compatibility with your telecom provider.
Migration flexibility
Connect existing carriers, PBXs, and devices
Direct Routing does not have to be a single cutover. Ribbon SBCs can support a phased migration while suitable legacy voice equipment remains connected.
Direct Routing SIP trunks
Redundant SIP trunks for failover
Analog or digital trunks (FXO)
Analog stations (FXS)
Legacy PBX integration
Contact-center integration
Simultaneous ringing (SIP forking)
Supported SIP phones and devices
Business continuity
Survivability and resiliency options
Cloud calling makes dependable Microsoft 365 and WAN access increasingly important. The solution can combine several continuity mechanisms.
Survivable Branch Appliance
Microsoft SBA support can provide branch calling continuity when Microsoft 365 connectivity is unavailable.
Resilient WAN links
Multiple network paths can provide rapid or seamless failover when a primary WAN connection is disrupted.
Multi-route software resiliency
High-availability software architectures can distribute connectivity across more than one route.
Redundant hardware
Physical redundancy can protect critical sites and on-premises telephony connectivity.
Enterprise-wide routing
Centralized routing and session control can bring existing branch PBXs, contact centers, analog devices, and new Teams users into one coordinated multi-site communications architecture.
Questions
Microsoft Teams Direct Routing FAQs
Direct Routing connects Microsoft Teams Phone to external phone lines through a compatible telecom provider and a Microsoft-certified Session Border Controller. Users can then make and receive business calls from Teams.
Microsoft requires a certified SBC to bridge Teams and the telephone network. The SBC secures voice traffic, handles carrier interoperability, supports routing and migration, and can provide resiliency functions.
Yes, where the existing equipment and interfaces are compatible. A phased design can support PBX coexistence, simultaneous ringing, analog trunks and stations, contact-center integration, and selected legacy devices while users move to Teams.
The design can include Microsoft SBA, resilient WAN connections, multi-route high availability, and redundant hardware. The right combination depends on site connectivity and business-continuity requirements.
Plan your Teams Direct Routing deployment
Share your Microsoft 365 licensing, carrier, sites, existing PBX, analog-device needs, and continuity requirements. We’ll help scope the appropriate certified SBC architecture.
Every deployment is validated against current Microsoft licensing, SBC certification, carrier interoperability, and site-resiliency requirements.
Request an assessment
Tell us what you need to connect, retain, or migrate.