How to Configure AudioCodes SBC for Microsoft Teams Direct Routing – Step-by-Step Guide

Microsoft Teams Direct Routing connects Teams Phone to a PSTN or SIP trunk through a certified Session Border Controller (SBC). This guide shows a practical deployment using an AudioCodes Mediant SBC.

Architecture: What We Are Building

Before You Start

The IP addresses, domains and telephone numbers above are examples only. Replace them with values from your environment.

Part 1 — Microsoft 365 Tenant

example.com

sip.example.com

sbc01.sip.example.com

sbc01.sip.example.com

Part 2 — DNS and TLS

sbc01.sip.example.com
        ↓
203.0.113.10
        ↓
AudioCodes SBC

sbc01.sip.example.com

Part 3 — AudioCodes SBC Foundation

Hostname:       SBC01
FQDN:           sbc01.sip.example.com
Management IP:  10.10.10.10
Gateway:        10.10.10.1
DNS:            10.10.10.20
NTP:            Configured

Part 4 — AudioCodes IP Groups and Proxy Sets

Teams Proxy Set
      ↓
Microsoft Teams SIP destination(s)

ITSP Proxy Set
      ↓
SIP provider destination

Teams IP Profile
      ↓
Teams IP Group

ITSP IP Profile
      ↓
ITSP IP Group

Example AudioCodes SBC Components

Before creating routing rules, it helps to understand how the main AudioCodes objects fit together. The following example is a simple two-sided SBC design: Microsoft Teams on one side and the SIP provider on the other.

AudioCodes documentation describes an IP Group as an IP entity with which the SBC communicates. For server-side entities, the IP Group is normally associated with a Proxy Set, and IP Groups are then used as the source and destination of IP-to-IP routing rules. citeturn0search24turn0search26

Example Component Map

Example 1 — Teams IP Group

A typical Teams IP Group can look like this. AudioCodes’ current Teams Direct Routing enterprise documentation includes parameters such as Type = Server, Proxy Set = Teams, IP Profile = Teams, Media Realm = MRWan, Local Host Name = the SBC FQDN, Teams Direct Routing Mode = Enable, with additional parameters depending on the deployment. citeturn0search24

Example 2 — ITSP IP Group

Create a second IP Group for your carrier.

Example 3 — Proxy Set

Think of the Proxy Set as the destination information used by an IP Group. The exact destination depends on whether you are connecting to Microsoft Teams, a carrier, or another SIP system.

Example 4 — IP Profile

Use separate profiles when Teams and the carrier require different SIP or media behavior.

IP Profile: Teams
    ↓
Teams IP Group

IP Profile: ITSP
    ↓
ITSP IP Group

Typical areas to review include:

• Codec negotiation
• DTMF
• Early media
• SIP header handling
• Media handling
• SRTP/security requirements
• Number manipulation requirements

Example 5 — Media Realms

A Media Realm helps the SBC organize media resources and network interfaces. A simple example might be:

The actual Media Realm design depends on your network topology, NAT, interfaces and whether Teams media bypass/local media optimization is being used.

Example 6 — IP-to-IP Routing Rules

Once the IP Groups, Proxy Sets and profiles exist, the SBC needs routing rules that connect the two sides.

This is the key concept: IP Groups identify the SIP entities; Proxy Sets identify destinations; IP Profiles control behavior; Media Realms provide media resources; IP-to-IP routing decides where the call goes.

Example 7 — Complete SBC Object Map

                    AUDIOCODES SBC

              +-----------------------+
              |     Teams SIP IF      |
              |       TLS : 5061      |
              +-----------+-----------+
                          |
                          v
              +-----------------------+
              |     IP Group: Teams   |
              +-----------+-----------+
                          |
                +---------+---------+
                |                   |
                v                   v
        Proxy Set: Teams      IP Profile: Teams
                |                   |
                +---------+---------+
                          |
                     Media Realm
                       MR-Teams
                          |
                    SIP Routing
                          |
                          v
              +-----------------------+
              |     IP Group: ITSP   |
              +-----------+-----------+
                          |
                +---------+---------+
                |                   |
                v                   v
        Proxy Set: ITSP       IP Profile: ITSP
                |                   |
                +---------+---------+
                          |
                     MR-ITSP
                          |
                          v
                   SIP Provider
                          |
                          v
                         PSTN

Example 8 — Optional Redundant SBC Design

For a larger production deployment, Microsoft Teams can use multiple Online PSTN Gateways in voice routes. Microsoft documents active and backup gateway examples in its Direct Routing routing guidance. citeturn0search0

                    Microsoft Teams
                          |
                 Voice Routing Policy
                          |
                     PSTN Usage
                          |
                     Voice Route
                    /          \
                   /            \
                  v              v
        sbc01.example.com   sbc02.example.com
                |                    |
                v                    v
             ITSP-1               ITSP-2
                \                    /
                 \                  /
                       PSTN

This allows you to design redundancy at the Teams gateway/routing layer, subject to your carrier and SBC architecture.

Part 5 — AudioCodes SIP Routing

Teams → AudioCodes SBC → SIP Provider → PSTN

PSTN → SIP Provider → AudioCodes SBC → Teams

+911122334455

Part 6 — Microsoft Teams Direct Routing

sbc01.sip.example.com

5061

New-CsOnlinePSTNGateway `
-Fqdn sbc01.sip.example.com `
-SIPSignalingPort 5061 `
-Enabled $true

DNS
 ↓
FQDN
 ↓
Certificate
 ↓
Firewall
 ↓
TLS
 ↓
SIP Interface
 ↓
AudioCodes Teams IP Group

India-PSTN

Set-CsOnlinePstnUsage `
-Identity Global `
-Usage @{Add="India-PSTN"}

New-CsOnlineVoiceRoute `
-Identity "India-PSTN" `
-NumberPattern "^\+91\d{10}$" `
-OnlinePstnGatewayList "sbc01.sip.example.com" `
-OnlinePstnUsages "India-PSTN"

Policy:
India-Direct-Routing

PSTN Usage:
India-PSTN

New-CsOnlineVoiceRoutingPolicy `
-Identity "India-Direct-Routing" `
-OnlinePstnUsages "India-PSTN"

Part 7 — Pilot User

user@example.com

Grant-CsOnlineVoiceRoutingPolicy `
-Identity "user@example.com" `
-PolicyName "India-Direct-Routing"

Part 8 — Testing

Teams
 ↓
AudioCodes SBC
 ↓
SIP Provider
 ↓
PSTN

PSTN
 ↓
SIP Provider
 ↓
AudioCodes SBC
 ↓
Microsoft Teams
 ↓
Pilot User

Part 9 — Troubleshooting

SBC Shows Disconnected

DNS
 ↓
FQDN
 ↓
Certificate
 ↓
Firewall
 ↓
TLS
 ↓
SIP Interface

Outbound Call Does Not Leave Teams

User
 ↓
Voice Routing Policy
 ↓
PSTN Usage
 ↓
Voice Route
 ↓
Online PSTN Gateway
 ↓
SBC

SBC Receives Call but Carrier Rejects It

Check the AudioCodes SIP trace and verify:

• Caller ID
• Called number
• Number format
• Carrier authentication
• Carrier IP allow-list
• Codec
• SIP headers
• Number manipulation

Call Connects but There Is No Audio

Concentrate on the media path:

Firewall
NAT
RTP ports
Media Realm
Codec
SBC media configuration

Part 10 — Backup and Production

SBC01-Teams-DirectRouting-Working-2026-08-14.ini

1 Pilot User
      ↓
5 Users
      ↓
20 Users
      ↓
50 Users
      ↓
100 Users
      ↓
Production

Final Production Checklist

Microsoft 365

• ☐ Domain verified
• ☐ SBC subdomain configured
• ☐ SBC FQDN decided

DNS and Security

• ☐ Public DNS works
• ☐ Firewall configured
• ☐ TLS certificate installed
• ☐ Certificate chain verified

AudioCodes

• ☐ Network configured
• ☐ SIP interface configured
• ☐ TLS context configured
• ☐ Teams IP Group configured
• ☐ ITSP IP Group configured
• ☐ Proxy Sets configured
• ☐ IP Profiles configured
• ☐ SIP routing configured
• ☐ Number manipulation configured

Teams

• ☐ SBC added as Online PSTN Gateway
• ☐ SBC connection verified
• ☐ PSTN Usage created
• ☐ Voice Route created
• ☐ Voice Routing Policy created
• ☐ Pilot user configured

Testing

• ☐ Teams → PSTN works
• ☐ PSTN → Teams works
• ☐ Two-way audio works
• ☐ Caller ID works
• ☐ DTMF works
• ☐ Transfer works
• ☐ Voicemail works

Conclusion

AudioCodes SBC + Microsoft Teams Direct Routing becomes much easier to troubleshoot when it is built one layer at a time.

Tenant → DNS → Certificate → SBC → Teams Gateway → PSTN Usage → Voice Route → Voice Routing Policy → Pilot User → Call Testing → Production

If something fails, return to the last successful checkpoint and troubleshoot that layer before changing anything else.