Microsoft Teams direct routing connects your existing telephone carrier to Teams so users call over the PSTN from inside Teams. This approach gives organisations control over carriers, numbers, and call routing while keeping Teams as the user interface.
TL;DR
- Direct Routing lets you use your carrier with Teams via an SBC, keeps existing numbers, lowers long-term costs, and supports hybrid work.
- It scales from small offices to multinational deployments.
- Consider Direct Routing when you want carrier choice and advanced PBX integration.
Overview & benefits
Direct Routing gives organisations flexible PSTN access through Teams.
The Microsoft Teams direct routing lets you connect a Session Border Controller (SBC) to Teams. Calls flow from PSTN carriers into Teams without using Microsoft Calling Plans.
Examples include keeping existing numbers, routing calls to remote employees, and integrating contact centre systems. 85% of Teams users prefer Direct Routing for flexibility and savings (2025).
How Direct Routing works
Direct Routing uses an SBC to bridge your carrier and Teams.
Summary: An SBC terminates SIP trunks and secures signalling to Microsoft’s Phone System. Calls arrive at your carrier, hit the SBC, and then reach Teams users via the Microsoft cloud.
Technical flow: carrier → SIP trunk → SBC → Microsoft Phone System → Teams client. This design supports desktop, mobile, and room systems like for meeting-room calling.
Setup steps
Start with a pilot and register an SBC in your tenant.
Steps: validate licensing, configure the SBC, create voice routing policies, and pilot test users. Use a phased rollout to limit disruption.
Required hardware and software
You need a certified SBC and SIP trunking from a carrier.
Software: Teams Phone licenses, SBC firmware that supports TLS and SRTP, and administration tools. Many vendors offer virtual SBCs for cloud-first setups.
Using Direct Routing with PBX
Direct Routing can sit in front of or behind an on-premises PBX.
This lets organisations reuse PBX features and dial plans while providing Teams as the primary client. Hybrid configurations reduce rip-and-replace cost.
Cost & scalability
Direct Routing often lowers telephony costs for medium and large organisations.
Cost drivers: carrier rates, SBC licensing, and Teams Phone licenses. You keep control over carrier contracts and negotiate bulk minutes.
Example: Porting numbers to a local UAE carrier and using a shared SIP trunk typically reduces international call costs for Dubai-based teams.
Pricing models and savings
Vendors price by trunk, concurrent calls, or per-user plans.
Choose pricing that matches call patterns. For mixed remote work, concurrent-call models can save money over per-user calling plans.
Scalability
Direct Routing scales horizontally using virtual SBCs and cloud SIP trunks.
Enterprises add capacity by deploying more SBC instances or increasing trunk bandwidth. This supports rapid growth across UAE and global offices.
Technical features & security
SBCs enforce signalling rules and protect SIP traffic to Teams.
Key features: codec negotiation, media bypass, TLS/SRTP encryption, and survivable branch appliances for resilience. These features improve call quality and reliability.
SBC requirements
SBCs must be certified for Microsoft Teams or listed as supported.
Certificates, routable IPs, and NAT traversal are mandatory. Many vendors publish compatibility matrices aligned with Microsoft guidance.
Security advantages
Direct Routing gives predictable security controls for voice traffic.
Use SBC-based policies to block toll fraud, apply encryption, and log call detail records for compliance.
Why Choose Direct Routing
Microsoft Teams Direct Routing offers businesses flexible PSTN connectivity without needing Microsoft Calling Plans. By linking a certified Session Border Controller (SBC) to Teams, companies can retain existing phone numbers, support remote staff, and integrate contact centre systems. In 2025, 85% of Teams users prefer Direct Routing for its cost-effectiveness and flexibility.
Understanding the Call Path
Direct Routing relies on an SBC to connect your telecom carrier to Microsoft’s Phone System. Incoming calls travel from the carrier through a SIP trunk to the SBC, which secures and forwards them to Teams users via the cloud. This system supports desktops, mobile devices, and meeting-room phones.
Getting Started with Deployment
Begin with a pilot program to validate licenses, configure the SBC, set up voice routing policies, and test selected users. A phased rollout helps avoid service disruption while ensuring smooth adoption.
Hardware and Software Essentials
A certified SBC and SIP trunk from a telecom provider are required. Teams Phone licenses, SBC firmware supporting TLS/SRTP, and administrative tools complete the setup. Virtual SBCs are also available for cloud-first environments.
Integrating with Existing PBX
Direct Routing can work alongside on-premises PBX systems, allowing organisations to reuse dial plans and PBX features while Teams becomes the primary calling platform. This hybrid setup reduces migration costs and complexity.
Recent updates
Microsoft has improved SIP options and management APIs for Direct Routing.
New features include enhanced diagnostics, better media bypass, and cloud-native SBC options for simpler deployments.
Migration and deployment checklist
Plan migration in stages and validate each step.
- Audit numbers and carriers.
- Select a certified SBC vendor or managed Direct Routing partner.
- Assign Teams Phone licenses and voice routing policies.
- Pilot with a group, then scale.
MAK Group and similar partners can provide managed services, device procurement, and onsite setup to speed rollouts.
FAQs
What is Microsoft Teams direct routing?
Direct Routing connects your carrier to Teams through an SBC for PSTN calling.
Do I need special licenses?
Yes. Teams Phone licenses are required for calling features in Teams.
Can I keep my existing phone numbers?
Yes. You can port numbers or continue using your current carrier agreements.
Is Direct Routing secure?
Yes. SBCs provide encryption, policy enforcement, and fraud controls.
How long does deployment take?
Small pilots can run in weeks; full rollouts may take months depending on scale.
Where can I get implementation help?
Managed service providers and certified Microsoft partners, including MAK Group, offer planning and deployment assistance.
