Mediant SBC with Mi cros oft Tea ms Dire ct Routing Enterprise M odel

Configuration Note
AudioCodes Mediant™ Family of Media Gateways & Session Border Controllers

Connecting AudioCodes' SBC to
Microsoft Teams Direct RoutingEnterprise Model

Contents

SBC for Teams DR Enterprise

Table of Contents
Notice ................................................................................................................................ iv
WEEE EU Directive ......................................................................................................................... iv
Customer Support ......................................................................................................................... iv
Stay in the Loop with AudioCodes ................................................................................................. iv
Abbreviations and Terminology ..................................................................................................... iv
Related Documentation .................................................................................................................. v
Document Revision Record ............................................................................................................. v
Documentation Feedback .............................................................................................................. vi

1

2

3

4

Introduction .................................................................................................................1
1.1

About Microsoft Teams Direct Routing ................................................................................ 1

1.2

About AudioCodes SBC Product Series ................................................................................. 1

1.3

Validated AudioCodes Version ............................................................................................. 2

Topology Example ........................................................................................................3
2.1

Enterprise Model Implementation ....................................................................................... 3

2.2

Environment Setup ............................................................................................................... 4

2.3

Infrastructure Prerequisites.................................................................................................. 5

Configuring Teams Direct Routing.................................................................................6
3.1

Prerequisites ......................................................................................................................... 6

3.2

SBC Domain Name in the Teams Enterprise Model .............................................................. 6

3.3

Example of the Enterprise Office 365 Tenant Direct Routing Configuration ........................ 8
3.3.1

Adding New SBC to Direct Routing ..................................................................................... 9

3.3.2

Adding Voice Route and PSTN Usage ................................................................................ 11

3.3.3

Adding Voice Routing Policy ............................................................................................. 13

3.3.4

Enabling Online User ........................................................................................................ 14

3.3.5

Assigning Online User to the Voice Routing Policy ............................................................ 14

3.3.6

Configuring with User Management Pack 365 (Optional) ................................................. 14

Configuring AudioCodes' SBC ......................................................................................15
4.1

SBC Configuration Concept in Teams Direct Routing .......................................................... 15

4.2

IP Network Interfaces Configuration .................................................................................. 16

4.3

4.4

4.2.1

Configuring VLANs ............................................................................................................ 17

4.2.2

Configuring Network Interfaces ........................................................................................ 18

SIP TLS Connection Configuration....................................................................................... 19
4.3.1

Configuring the NTP Server Address ................................................................................. 19

4.3.2

Creating a TLS Context for Teams Direct Routing .............................................................. 20

4.3.3

Generating a CSR and Obtaining the Certificate from a Supported CA .............................. 21

4.3.4

Deploying the SBC and Root / Intermediate Certificates on the SBC ................................. 23

Method for Generating and Installing the Wildcard Certificate ......................................... 25- ii -

Contents

SBC for Teams DR Enterprise

4.5

Deploying Trusted Root Certificate for MTLS connection ................................................... 25

4.6

Configuring Media Realm ................................................................................................... 26

4.7

Configuring SIP Signaling Interfaces ................................................................................... 27

4.8

Configuring Proxy Sets and Proxy Address ......................................................................... 28

4.9

4.8.1

Configuring Proxy Sets...................................................................................................... 28

4.8.2

Configuring Proxy Addresses ............................................................................................ 29

Configuring Coder Groups .................................................................................................. 30

4.10 Configuring IP Profiles ........................................................................................................ 31
4.11 Configuring IP Groups ......................................................................................................... 33
4.12 Configuring SRTP ................................................................................................................ 34
4.13 Configuring Message Manipulation Rules .......................................................................... 35
4.14 Configuring Message Condition Rules ................................................................................ 36
4.15 Configuring Classification Rules .......................................................................................... 37
4.16 Configuring IP-to-IP Call Routing Rules ............................................................................... 38
4.17 Configuring Firewall Settings .............................................................................................. 39
4.18 Configuring SBC To Play Music On Hold (Optional) ............................................................ 40

5

Verifying the Pairing Between the SBC and Direct Routing ..........................................41

6

Making a Test Call.......................................................................................................42A

Syntax Requirements for SIP Messages 'INVITE' and 'OPTIONS' ..................................43

B

A.1

Terminology........................................................................................................................ 43

A.2

Syntax Requirements for 'INVITE' Messages ...................................................................... 43

A.3

Requirements for 'OPTIONS' Messages Syntax................................................................... 44

A.4

Connectivity Interface Characteristics ................................................................................ 44

SIP Proxy Direct Routing Requirements ......................................................................46
B.1

Failover Mechanism ........................................................................................................... 46- iii -

Notices

SBC for Teams DR Enterprise

NoticeNoticeInformation contained in this document is believed to be accurate and reliable at the time ofprinting. However, due to ongoing product improvements and revisions, AudioCodes cannot
guarantee accuracy of printed material after the Date Published nor can it accept responsibility forerrors or omissions. Updates to this document can be downloaded fromhttps://www.audiocodes.com/library/technical-documents.
This document is subject to change without notice.
Date Published: June-12-2023

WEEE EU Directive
Pursuant to the WEEE EU Directive, electronic and electrical waste must not be disposed of withunsorted waste. Please contact your local recycling authority for disposal of this product.

Customer Support
Customer technical support and services are provided by AudioCodes or by an authorized
AudioCodes Service Partner. For more information on how to buy technical support for AudioCodes
products
andforcontact
information,pleasevisit
ourwebsiteathttps://www.audiocodes.com/services-support/maintenance-and-support.

Stay in the Loop with AudioCodes

Abbreviations and Terminology
Each abbreviation, unless widely used, is spelled out in full when first used.

- iv -

Notices

SBC for Teams DR Enterprise

Related Documentation
Document NameMediant 500 Gateway & E-SBC User's ManualMediant 500L Gateway & E-SBC User's ManualMediant 800 Gateway & E-SBC User's ManualMediant 1000B Gateway & E-SBC User's ManualMediant 2600 SBC User's ManualMediant 4000 SBC User's ManualMediant 9000 SBC User's ManualMediant Software SBC User's Manual
Gateway and SBC CLI Reference Guide
SIP Message Manipulation Reference Guide

Document Revision Record
LTRT
47B

Description

LTRT-TAP

Added Chapter “Direct Routing Media Optimization” for Direct Routing Media
Optimization Routing between Microsoft Phone System (Cloud PBX) and SBC devices.

LTRT-TAP

Updates in Section “Configuring SBC for Media Optimization Proxy SBC”; Site SBCs Reconfiguration.

13320

Updates to IP Profile configuration in Chapter “Configuring SBC for Media Optimization
Proxy SBC” and Chapter “Site SBCs Re-configuration”

13320

Updates to Table "Configuration Example: Teams IP Profile” (updated parameters Remote
REFER Mode and Remote 3xx Mode), Added Table “Configuration Example: SIP Trunk IP
Profile (toward Remote SBC)”, Changed title for Table “Configuration Example: Teams IP
Profile (through the Proxy SBC) and Table “Configuration Example: SIP Trunk IP Profile(toward SIP Provider/ Media Gateway)”.

13321

Updates to the names of the IP Group Media optimization parameters to “Local Media
Optimization and “Teams Local Media Optimization Initial Behavior”, Added Appendix “IP
Profile – Quick Guidelines”

13322

Added Sections “Adopt Gateway Application to Work with Local Media Optimization” andAppendix C “Local Media Optimization – Quick Guidelines”.

13323

Update to the “Related Documentation” table to include the Mediant 1000B Gateway & ESBC product.

13324

All information related to Local Media Optimization was removed to a separate document.
“Connecting AudioCodes' SBC to Microsoft Teams Direct Routing Local Media
Optimization”.

13325

Update for Message Manipulation rule towards Microsoft Teams.

13326“SipSignallingPort” replaced by “SipSignalingPort”.

13327

Update to the Firewall Table Rules table with two additional IP addresses of the new
infrastructure in Japan.

-v-

Notices

SBC for Teams DR Enterprise

LTRT

Description

47B

13328

Update to SIP Trunk IP Profile and validated firmware version.

13329

Added section for overcoming problem of not playing music on hold during conversationaltransfer.

13331

Remote Replaces Mode parameter with value “Handle Locally” was added to the Teams IP
Profile due to new Microsoft requirements. The Classification rule was updated.
Update to the Firewall Table Rules table due to new Microsoft requirements.

13332

TLS Root Certificate Authority updated by Microsoft.

13334

Updated Classification Table with stricter rules to only allow for documented Microsoft SIP
Proxies.

13336

Note added detailing deployment in Office 365 GCC DoD and GCC High environments.

13339

TLS Private Key size of 1024 was removed. Microsoft subnets were updated in theClassification and Firewall tables.

Documentation Feedback
AudioCodes continually strives to produce high quality documentation. If you have any comments(suggestions or errors) regarding this document, please fill out the Documentation Feedback formon our website at https://online.audiocodes.com/documentation-feedback.

- vi -

1. Introduction

1

SBC for Teams DR Enterprise

Introduction
This document describes how to connect AudioCodes' SBC to Teams Direct Routing Enterprise modeland refers to the AudioCodes SBC configuration only.
For configuring the Office 365 side, please refer tohttps://docs.microsoft.com/en-us/microsoftteams/direct-routing-configure.
This document is intended for IT or telephony professionals.

To zoom in on screenshots of example Web interface configurations, press Ctrl and +.

1.1

About Microsoft Teams Direct Routing
Teams Direct Routing allows connecting a customer-provided SBC to Microsoft Phone System. The
customer-provided SBC can be connected to almost any telephony trunk or connect with third-party
PSTN equipment. The connection allows:

1.2◼

Using virtually any PSTN trunk with Microsoft Phone System◼

Configuring interoperability between customer-owned telephony equipment, such as third-party
PBXs, analog devices, and Microsoft Phone System

About AudioCodes SBC Product Series
AudioCodes' family of SBC devices enables reliable connectivity and security between the enterprise's
VoIP network and the service provider's VoIP network.
The SBC provides perimeter defense as a way of protecting enterprises from malicious VoIP attacks;
mediation for allowing the connection of any PBX and/or IP-PBX to any service provider; and Service
Assurance for service quality and manageability.
Designed as a cost-effective appliance, the SBC is based on field-proven VoIP and network services witha native host processor, allowing the creation of purpose-built multiservice appliances, providingsmooth connectivity to cloud services, with integrated quality of service, SLA monitoring, security andmanageability. The native implementation of SBC provides a host of additional capabilities that are notpossible with standalone SBC appliances such as VoIP mediation, PSTN access survivability, and thirdparty value-added services applications. This enables enterprises to utilize the advantages of converged
networks and eliminate the need for standalone appliances.
AudioCodes' SBC is available as an integrated solution running on top of its field-proven Mediant Media
Gateway and Multi-Service Business Router platforms, or as a software-only solution for deployment
with third-party hardware. The SBC can be offered as a Virtualized SBC, supporting the following
platforms: Hyper-V, AWS, AZURE, AWP, KVM and VMWare.

-1-1. Introduction

1.3

SBC for Teams DR Enterprise

Validated AudioCodes Version
Microsoft has successfully conducted validation tests with AudioCodes' Mediant SBC Ver. 7.40A.250.
Previous certified firmware versions are 7.20A.258 and 7.40A.100. For an updated list, refer to List of
Session Border Controllers certified for Direct Routing.
For implementing Microsoft Teams Direct Routing based on the configuration described inthis document, AudioCodes SBC must be installed with a License Key that includes thefollowing features:
◼

◼
◼
◼
◼

MSFT (general Microsoft license)
Note: By default, all AudioCodes media gateways and SBCs are shipped with this license(except MSBR products, Mediant 500 SBC, and Mediant 500 Media Gateway).
SW/TEAMS (Microsoft Teams license)
Number of SBC sessions (based on requirements)
Transcoding sessions (only if media transcoding is needed)
Coders (based on requirements)

For more information about the License Key, contact your AudioCodes sales representative.

-2-2. Topology Example

2

SBC for Teams DR Enterprise

Topology Example
Teams Direct Routing can be implemented in the Enterprise or Hosting Models.

2.1

Enterprise Model Implementation
The figures below show examples of the connection topology between AudioCodes SBC and Teams
Direct Routing Enterprise Model SIP Trunk with Teams Direct Routing Enterprise Model assume thefollowing topology setup:◼

Enterprise deployed with the IP-PBX (optional) and administrator's management station, locatedon the LAN.

◼

Enterprise deployed with Teams Phone System Direct Routing Interface located on the WAN for
enhanced communication within the Enterprise.

◼

Enterprise wishes to offer its employees enterprise-voice capabilities and to connect theEnterprise to the PSTN network using Teams Direct Routing Enterprise Model's SIP Trunking
service.

◼

AudioCodes SBC is implemented to interconnect between the SIP Trunk and Teams Direct Routing
located in the WAN.

The figure below illustrates this topology example:
Figure 1: Connection Topology with SIP Trunk on the LAN

Figure 2: Connection Topology with SIP Trunk on the WAN

Enterprise Network

Management
Station (OAMP)

Phone System(Cloud PBX)IP-PBX

PSTN-3-

2. Topology Example

SBC for Teams DR Enterprise

◼

◼

2.2

This document shows how to configure the connection between AudioCodes' SBC andthe Teams Direct Routing with a generic SIP Trunk. For detailed configuration of otherentities in the deployment such as the SIP Trunk Provider and the local IP-PBX, refer to
AudioCodes' SIP Trunk Configuration Notes (in the interoperability suite of documents).
This document only includes basic Teams Direct Routing configuration. Customers who
would like to implement Direct Routing Local Media Optimization Routing between
Microsoft Phone System (Cloud PBX) and SBC devices, refer to AudioCodes’ Connecting
AudioCodes' SBC to Microsoft Teams Direct Routing Local Media Optimization
Configuration Notes document.

Environment Setup
The example topology includes the following environment setup:
Table 1: Environment Setup
Area

Setup
◼

Network◼

Signaling
Transcoding◼
◼
◼

CodecsTranscoding
Media
Transcoding◼
◼
◼

Teams Direct Routing environment is located on the Enterprise's (or Service
Provider’s) WAN
Teams Direct Routing Enterprise Model SIP Trunk is located on the LAN
Teams Direct Routing operates with SIP-over-TLS transport type
Teams Direct Routing Enterprise Model SIP Trunk operates with SIP-over-UDP
transport type
Teams Direct Routing supports G.711A-law, G.711U-law, G.729 and SILK (NB
and WB) coders
Teams Direct Routing Enterprise Model SIP Trunk supports G.711A-law,
G.711U-law, and G.729 coders
Teams Direct Routing operates with SRTP media type
Teams Direct Routing Enterprise Model SIP Trunk operates with RTP media
type

-4-

2. Topology Example

2.3

SBC for Teams DR Enterprise

Infrastructure Prerequisites
The table below shows the list of infrastructure prerequisites for deploying Teams Direct Routing.
Table 2-2: Infrastructure Prerequisites
Infrastructure Prerequisite

Details

Certified Session Border Controller (SBC)
SIP Trunks connected to the SBC
Enterprise Office 365 Tenant
Domains
Public IP address for the SBC
Fully Qualified Domain Name (FQDN) for the SBC
See Microsoft's document Plan Direct Routing.

Public DNS entry for the SBC
Public trusted certificate for the SBC
Firewall ports for Direct Routing Signaling
Firewall IP addresses and ports for Direct Routing MediaMedia Transport Profile
Firewall ports for Teams Clients Media-5-

3. Configuring Teams Direct Routing

3

SBC for Teams DR Enterprise

Configuring Teams Direct RoutingThis section describes an example of Teams Direct Routing configuration to operate with AudioCodes
SBC.

3.1

Prerequisites
Before you begin configuration, make sure you have the following for every SBC you want to pair:

3.2◼

Public IP address◼

FQDN name matching SIP addresses of the Teams users◼

Public certificate issued by one of the supported CAs

SBC Domain Name in the Teams Enterprise Model
The SBC domain name must be from one of the names registered in 'Domains' of the Enterprise Office
365 tenant. You cannot use the *.onmicrosoft.com tenant for the domain name. For example, in Figure
3, the administrator registered the following DNS names for the Enterprise Office 365 tenant:Table 3: DNS Names Registered by an Administrator for an Enterprise Office 365 Tenant
DNS name

Can be used
for SBC FQDN

Examples of FQDN names
Valid names:◼
◼

ACeducation.info

Yes◼

sbc.ACeducation.info
ussbcs15.ACeducation.info
europe.ACeducation.info

Invalid name:sbc1.europe.ACeducation.info (requires registering
domain name europe.atatum.biz in 'Domains' first)
adatumbiz.onmicrosoft.com

No

Using *.onmicrosoft.com domains is not supported for
SBC names
Valid names:◼
◼

hybridvoice.org

Yes◼

sbc1.hybridvoice.org
ussbcs15.hybridvoice.org
europe.hybridvoice.org

Invalid name:sbc1.europe.hybridvoice.org (requires registering domainname europe.hybridvoice.org in 'Domains' first).
Users can be from any SIP domain registered for the Enterprise Office 365 tenant. For example, you canprovide users user@ACeducation.info with the SBC FQDN int-sbc1.audctrunk.aceducation.info so longas both names are registered for this tenant.

-6-3. Configuring Teams Direct Routing

SBC for Teams DR Enterprise

Figure 3: Example of Registered DNS Names

During creation of the Domain you will be forced to create public DNS record(int-sbc1.audctrunk.aceducation.info in our example.)-7-

3. Configuring Teams Direct Routing

3.3

SBC for Teams DR Enterprise

Example of the Enterprise Office 365 Tenant Direct Routing
Configuration
Configuration can be done using the web or with PowerShell. For the web, login to the Teams Admin
Center (https://admin.teams.microsoft.com) with Tenant Administrator credentials.
Figure 4: Teams Admin Center-8-

3. Configuring Teams Direct Routing

3.3.1

SBC for Teams DR Enterprise

Adding New SBC to Direct Routing
The procedure below describes how add a new SBC to Direct Routing.
To add New SBC to Direct Routing:
1.

In the web interface, select Voice, and then click Direct Routing.

2.

Under SBCs click Add.
Figure 5: Add new SBC to Direct Routing

3.

Configure SBC.
Figure 6: Configure new SBC-9-3. Configuring Teams Direct Routing

SBC for Teams DR Enterprise

You can use the following PowerShell command for creating a new Online PSTN Gateway:
New-CsOnlinePSTNGateway -Identity intsbc1.audctrunk.aceducation.info -SipSignalingPort 5061 ForwardCallHistory $True -ForwardPai $True -MediaBypass $True Enabled $True
Currently, enabling MediaBypass is available only through PowerShell.

- 10 -

3. Configuring Teams Direct Routing

3.3.2

SBC for Teams DR Enterprise

Adding Voice Route and PSTN Usage
The procedure below describes how add a voice route and PSTN usage.
To add voice route and PSTN usage:
1.

In the web interface, under Direct Routing, select Voice routes, and then click Add.
Figure 7: Add New Voice Route2.

Create a new Voice Route and associate it with the SBC, configured in the previous step.
Figure 8: Associate SBC with new Voice Route- 11 -

3. Configuring Teams Direct Routing

3.

SBC for Teams DR Enterprise

Add new (or associate existing) PSTN usage.
Figure 9: Associate PSTN Usage with New Voice RouteThe same operations can be done using following PowerShell commands:
1.

Creating PSTN Usage:
Set-CsOnlinePstnUsage -Identity Global -Usage @{Add="Interop"}2.

Creating new Online Voice Route and associating it with PSTN Usage:
New-CsOnlineVoiceRoute -Identity "audc-interop" -NumberPattern"^\+" -OnlinePstnGatewayList int-sbc1.audctrunk.aceducation.info-Priority 1 -OnlinePstnUsages "Interop"- 12 -

3. Configuring Teams Direct Routing

3.3.3

SBC for Teams DR Enterprise

Adding Voice Routing Policy
The procedure below describes how add a voice routing policy
To add voice routing policy:
1.

In the web interface, under Voice, select Voice routing policies and click Add.
Figure 10: Add New Voice Routing Policy2.

Create a new Voice Routing Policy and associate it with PSTN Usage, configured in the previous
step.
Figure 11: Associate PSTN Usage with New Voice Routing Policy- 13 -

3. Configuring Teams Direct Routing

SBC for Teams DR Enterprise

The same operations can be done using following PowerShell command:
New-CsOnlineVoiceRoutingPolicy "audc-interop" -OnlinePstnUsages"Interop"
The commands specified in Sections 3.3.4 and 3.3.5, should be run for each Teams user in theEnterprise Office 365 tenant. They are currently available through PowerShell only.

3.3.4

Enabling Online User
Use following PowerShell command for enabling online user:
Set-CsPhoneNumberAssignment -Identity user1@company.com EnterpriseVoiceEnabled $true
Set-CsPhoneNumberAssignment -Identity user1@company.com -PhoneNumber+12345678901 -PhoneNumberType DirectRouting

3.3.5

Assigning Online User to the Voice Routing Policy
Use following PowerShell command for assigning online user to the Voice Route:
Grant-CsOnlineVoiceRoutingPolicy -PolicyName "audc-interop" -Identity user1@company.com

3.3.6

Configuring with User Management Pack 365 (Optional)
As an alternative to PowerShell commands, AudioCodes recommend using User Management Pack 365(UMP365). UMP365 provides a simple web-portal user interface for configuring and managing theOnline Voice Route and associating it with PSTN Usage and PSTN Gateway. See examples below:
Figure 12: Example of Adding new Voice Route

Figure 13: Example of Voice Routes Table- 14 -

4. Configuring AudioCodes' SBC

4

SBC for Teams DR Enterprise

Configuring AudioCodes' SBC
This section provides example of step-by-step procedures on how to configure AudioCodes SBC forinterworking between Teams Direct Routing and the Teams Direct Routing Enterprise Model SIP Trunk.
These configuration procedures are based on the topology example described in Section 2.1 on page 3,
and includes the following main areas:◼

SBC LAN interface – administrator's management station and Teams Direct Routing Enterprise
Model SIP Trunking (depend on topology) environment.

◼

SBC WAN interface - Teams Direct Routing Enterprise Model SIP Trunking (depend on topology)
and Teams Direct Routing environment.

This configuration is done using the SBC's embedded Web server (hereafter, referred to as Web
interface).
◼

◼

4.1

For implementing Teams Direct Routing based on the configuration described in thissection, AudioCodes SBC must be installed with a License Key. For more information, see
Section 1.3 on page 2.
The scope of this document does not cover all security aspects for configuring this
topology. Comprehensive security measures should be implemented per yourorganization's security policies. For security recommendations on AudioCodes’ products,
refer to the Recommended Security Guidelines document, which can be found at
AudioCodes web site.

SBC Configuration Concept in Teams Direct Routing
The diagram below represents AudioCodes’ device configuration concept.
Figure 14: SBC Configuration Concept
Proxy Set

IP Group

SIP
Interface

SBC

SIP
Trunk

SIP
Interface

IP Group

Proxy Set

Phone System- 15 -

4. Configuring AudioCodes' SBC

4.2

SBC for Teams DR EnterpriseIP Network Interfaces Configuration
This section describes how to configure the SBC's IP network interfaces. There are several ways to deploy
the SBC:◼

SBC interfaces with the following IP entities:•

Teams Direct Routing, located on the WAN•

SIP Trunk - located on the LAN (or WAN)◼

SBC connects to the WAN through a DMZ network◼

Physical connection: The type of physical connection depends on the method used to connect tothe Enterprise's network. In the interoperability test topology, SBC connects to the LAN and DMZ
using dedicated Ethernet ports (i.e., two ports and two network cables are used).

◼

SBC also uses two logical network interfaces:•

LAN (VLAN ID 1)•

DMZ (VLAN ID 2)
Figure 15: Network Interfaces in the Topology with SIP Trunk on the LAN
LAN Port

Session Border Controller

Vlan ID 1

Vlan ID 2

LANManagement
Station (OAMP)LAN Port

DMZ
WAN

Phone System
FirewallITSP

Figure 16: Network Interfaces in the Topology with SIP Trunk on the WAN
LAN Port

Session Border Controller

Vlan ID 1LAN

LAN Port

Vlan ID 2

DMZ

Phone System
WAN

Management
Station (OAMP)

FirewallITSPThis Configuration Notes document provides an example topology with a SIP Trunk on the LAN.

- 16 -

4. Configuring AudioCodes' SBC

4.2.1

SBC for Teams DR Enterprise

Configuring VLANs
This section describes how to define VLANs for each of the following interfaces:◼

LAN (assigned the name "LAN_IF")◼

WAN (assigned the name "WAN_IF")

To configure the VLANs:
1.

Open the Ethernet Device table (Setup menu > IP Network tab > Core Entities folder > Ethernet
Devices).

2.

There will be one existing row for VLAN ID 1 and underlying interface GROUP_1.

3.

Add another VLAN ID 2 for the WAN side.
Figure 17: Configured VLAN IDs in Ethernet Device- 17 -

4. Configuring AudioCodes' SBC

4.2.2

SBC for Teams DR Enterprise

Configuring Network Interfaces
This section describes how to configure the IP network interfaces for each of the following interfaces:◼

LAN Interface (assigned the name "LAN_IF")◼

WAN Interface (assigned the name "WAN_IF")

To configure network parameters for both LAN and WAN interfaces:
1.

Open the IP Interfaces table (Setup menu > IP Network tab > Core Entities folder > IP Interfaces).

2.

Configure the IP interfaces as follows (your network parameters might be different):
Table 4: Configuration Example of the Network Interface Table

Index

Application
Types

InterfaceMode

IP Address

PrefixLengthGateway

DNS

I/F Name

Ethernet
Device0

OAMP+ Media +Control

IPv4 Manual

10.15.77.77

16

10.15.0.1

10.15.27.1

LAN_IFvlan 1

1

Media + Control(as thisinterface points
to the internet,
enabling OAMP
is notrecommended)

IPv4 Manual

195.189.192.157(DMZ IP address of
SBC)

25

195.189.192.129(router's IP
address)

According to
your Internet
provider's
instructions

WAN_IFvlan 2The configured IP network interfaces are shown below:
Figure 18: Configuration Example of the Network Interface Table- 18 -

4. Configuring AudioCodes' SBC

4.3

SBC for Teams DR Enterprise

SIP TLS Connection Configuration
This section describes how to configure the SBC for using a TLS connection with the Teams Direct Routing
Phone System. This configuration is essential for a secure SIP TLS connection. The configuration
instructions example in this section are based on the following domain structure that must be
implemented as part of the certificate which must be loaded to the host SBC:◼

CN: int-sbc1.audctrunk.aceducation.info◼

SAN: int-sbc1.audctrunk.aceducation.info

This certificate module is based on the Service Provider's own TLS Certificate. For more certificate
structure options, see Microsoft Teams Direct Routing documentation.
The Phone System Direct Routing Interface allows only TLS connections from SBCs for SIP traffic with acertificate signed by one of the Trusted Certification Authorities.
Currently, supported Certification Authorities can be found in the following link:
https://docs.microsoft.com/en-us/microsoftteams/direct-routing-plan#public-trusted-certificate-forthe-sbc

4.3.1

Configuring the NTP Server AddressThis section describes how to configure the NTP server's IP address. It is recommended to implement an
NTP server (Microsoft NTP server or another global server) to ensure that the SBC receives the current
date and time. This is necessary for validating certificates of remote parties. It is important, that NTP
Server will locate on the OAMP IP Interface (LAN_IF in our case) or will be accessible through it.
To configure the NTP server address:
1.

Open the Time & Date page (Setup menu > Administration tab > Time & Date).

2.

In the 'Primary NTP Server Address' field, enter the IP address of the NTP server (e.g., 10.15.27.1).
Figure 19: Configuring NTP Server Address

3.

Click Apply.

- 19 -

4. Configuring AudioCodes' SBC

4.3.2

SBC for Teams DR Enterprise

Creating a TLS Context for Teams Direct Routing
The section below shows how to request a certificate for the SBC WAN interface and to configure it
based on the example of DigiCert Global Root CA. The certificate is used by the SBC to authenticate theconnection with Teams Direct Routing.
The procedure involves the following main steps:a.

Creating a TLS Context for Teams Direct Routingb.

Generating a Certificate Signing Request (CSR) and obtaining the certificate from a supported
Certification Authorityc.

Deploying the SBC and Root / Intermediate certificates on the SBC

To create a TLS Context for Teams Direct Routing:
1.

Open the TLS Contexts page (Setup menu > IP Network tab > Security folder > TLS Contexts).

2.

Create a new TLS Context by clicking +New at the top of the interface, and then configure theparameters using the table below as reference.
Table 5: New TLS Context
Index

Name

TLS Version

1

Teams (arbitrary descriptive name)TLSv1.2

All other parameters can be left unchanged with their default values.

The table above exemplifies configuration focusing on interconnecting SIP and media. Youmight want to configure additional parameters according to your company's policies. For
example, you might want to configure Online Certificate Status Protocol (OCSP) to check if
SBC certificates presented in the online server are still valid or revoked. For more informationon the SBC's configuration, see the User's Manual, available for download fromhttps://www.audiocodes.com/library/technical-documents.
Figure 20: Configuration of TLS Context for Direct Routing- 20 -

4. Configuring AudioCodes' SBC

3.

SBC for Teams DR Enterprise

Click Apply; you should see the new TLS Context and option to manage the certificates at thebottom of 'TLS Context' table.

Figure 21: Configured TLS Context for Direct Routing and Interface to Manage the Certificates

4.3.3

Generating a CSR and Obtaining the Certificate from a Supported CA
This section shows how to generate a Certificate Signing Request (CSR) and obtain the certificate from a
supported Certification Authority.
To generate a Certificate Signing Request (CSR) and obtain the certificate from a supported
Certification Authority:
1.

Open the TLS Contexts page (Setup menu > IP Network tab > Security folder > TLS Contexts).

2.

In the TLS Contexts page, select the Teams TLS Context index row, and then click the Change
Certificate link located below the table; the Context Certificates page appears.

3.

Under the Certificate Signing Request group, do the following:a.

In the 'Common Name [CN]' field, enter the SBC FQDN name (based on example above, intsbc1.audctrunk.aceducation.info ).

b.

In the '1st Subject Alternative Name [SAN]' field, change the type to ‘DNS’, and then enter
the SBC FQDN name (based on the example above, int-sbc1.audctrunk.aceducation.info ).
The domain portion of the Common Name [CN] and 1st Subject Alternative Name [SAN] mustmatch the SIP suffix configured for Office 365 users.

c.

Enter the rest of the request fields according to your security provider's instructions.

d.

Click the Create CSR button; a textual certificate signing request is displayed in the area
below the button:- 21 -

4. Configuring AudioCodes' SBC

SBC for Teams DR Enterprise

Figure 22: Example of Certificate Signing Request – Creating CSR

4.

Copy the CSR from the line "----BEGIN CERTIFICATE" to "END CERTIFICATE REQUEST----" to a text
file (such as Notepad), and then save it to a folder on your computer with the file name, forexample certreq.txt.

5.

Send certreq.txt file to the Certified Authority Administrator for signing.

- 22 -

4. Configuring AudioCodes' SBC

4.3.4

SBC for Teams DR Enterprise

Deploying the SBC and Root / Intermediate Certificates on the SBC
After obtaining the SBC signed and Trusted Root/Intermediate Certificate from the CA, install thefollowing:◼

SBC certificate◼

Root / Intermediate certificates

To install the SBC certificate:1.

In the SBC's Web interface, return to the TLS Contexts page and do the following:a.

In the TLS Contexts page, select the required TLS Context index row, and then click the
Change Certificate link located below the table; the Context Certificates page appears.

b.

Scroll down to the Upload certificates files from your computer group, click the Choose Filebutton corresponding to the 'Send Device Certificate...' field, navigate to the certificate fileobtained from the CA, and then click Load File to upload the certificate to the SBC.

Figure 23: Uploading the Certificate Obtained from the Certification Authority

2.

Validate that the certificate was uploaded correctly: A message indicating that the certificate was
uploaded successfully is displayed in blue on the lower part of the page:
Figure 24: Message Indicating Successful Upload of the Certificate

3.

In the SBC's Web interface, return to the TLS Contexts page, select the required TLS Context index
row, and then click the Certificate Information link, located at the bottom of the TLS. Then
validate the Key size, certificate status and Subject Name:- 23 -

4. Configuring AudioCodes' SBC

SBC for Teams DR Enterprise

Figure 25: Certificate Information Example

4.

5.

In the SBC's Web interface, return to the TLS Contexts page.
a.

In the TLS Contexts page, select the required TLS Context index row, and then click theTrusted Root Certificates link, located at the bottom of the TLS Contexts page; the Trusted
Certificates page appears.

b.

Click the Import button, and then select all Root/Intermediate Certificates obtained fromyour Certification Authority to load.

Click OK; the certificate is loaded to the device and listed in the Trusted Certificates store:
Figure 26: Example of Configured Trusted Root Certificates- 24 -

4. Configuring AudioCodes' SBC

4.4

SBC for Teams DR Enterprise

Method for Generating and Installing the Wildcard Certificate
To use the same certificate on multiple devices, you may prefer using 3rd party application (e.g., DigiCert
Certificate Utility for Windows) to process the certificate request from your Certificate Authority on
another machine, with this utility installed.
After you've processed the certificate request and response using the DigiCert utility, test the certificate
private key and chain and then export the certificate with private key and assign a password.
To install the certificate:

4.5

1.

Open the TLS Contexts page (Setup menu > IP Network tab > Security folder > TLS Contexts).

2.

In the TLS Contexts page, select the required TLS Context index row, and then click the Change
Certificate link located below the table; the Context Certificates page appears.

3.

Scroll down to the Upload certificates files from your computer group and do the following:a.

Enter the password assigned during export with the DigiCert utility in the 'Private key passphrase' field.

b.

Click the Choose File button corresponding to the 'Send Private Key...' field and then selectthe SBC certificate file exported from the DigiCert utility.

Deploying Trusted Root Certificate for MTLS connection
Loading Trusted Root Certificates to AudioCodes' SBC is mandatory when implementing an
MTLS connection with the Microsoft Teams network.
Microsoft 365 is updating services powering messaging, meetings, telephony, voice, andvideo to use TLS certificates from a different set of Root Certificate Authorities (CAs). For
more details of the new Root CAs, refer to Microsoft technical guidance at Office TLS
Certificate Changes. Services began transitioning to the new Root CAs (e.g., DigiCert)
beginning in January 2022 and will continue through October 2022. During this migration
period, it’s possible to load both the old (Baltimore) and the new (DigiCert) Root certificate
to the same TLS Context.
The DNS name of the Teams Direct Routing interface is sip.pstnhub.microsoft.com. In this interface, acertificate is presented which is signed by DigiCert with:
Serial Number: 0x033af1e6a711a9a0bb2864b11d09fae5,
SHA-1 Thumbprint: DF3C24F9BFD666761B268073FE06D1CC8D4F82A4 andSHA-256 Thumbprint: CB3CCBB76031E5E0138F8DD39A23F9DE47FFC35E43C1144CEA27D46A5AB1CB5F.
To trust this certificate, your SBC must have the certificate in Trusted Certificates storage. Download
the DigiCert Global Root G2 (df3c) certificate in PEM format fromhttps://www.digicert.com/kb/digicert-root-certificates.htm and follow the steps above to import thecertificate to the Trusted Root storage.
Before importing the DigiCert Root Certificate into AudioCodes' SBC, make sure it's in .PEM
or .PFX format. If it isn't, you need to convert it to .PEM or .PFX format, otherwise the 'Failed
to load new certificate' error message is displayed. To convert to PEM format, use Windows
local store on any Windows OS and then export it as 'Base-64 encoded X.509 (.CER)
certificate'.

- 25 -

4. Configuring AudioCodes' SBC

4.6

SBC for Teams DR Enterprise

Configuring Media RealmMedia Realms allow dividing the UDP port ranges for use on different interfaces. In the example below,
two Media Realms are configured:◼

One for the LAN interface, with the UDP port starting at 6000 and the number of media session
legs 100 (you need to calculate number of media session legs based on your usage)◼

One for the WAN interface, with the UDP port range starting at 7000 and the number of media
session legs 100

To configure Media Realms:
1.

Open the Media Realms table (Setup menu > Signaling & Media tab > Core Entities folder >Media Realms).

2.

Configure Media Realms as follows (you can use the default Media Realm (Index 0), but modify
it):
Table 6: Configuration Example Media Realms in Media Realm Table

Index

Name

0

MRLan
(arbitrary name)

1

MRWan
(arbitrary name)

Topology
LocationUp

IPv4 Interface
Name

Port Range
Start

Number of Media Session Legs

LAN_IF

6000

100 (media sessions assigned withport range)

WAN_IF

7000

100 (media sessions assigned withport range)

The configured Media Realms are shown in the figure below:
Figure 27: Configuration Example Media Realms in Media Realm Table- 26 -

4. Configuring AudioCodes' SBC

4.7

SBC for Teams DR Enterprise

Configuring SIP Signaling Interfaces
This section shows how to configure a SIP Signaling Interfaces. A SIP Interface defines a listening port
and type (UDP, TCP, or TLS) for SIP signaling traffic on a specific logical IP network interface (configuredin the Interface Table above) and Media Realm.
Note that the configuration of a SIP interface for the SIP Trunk shows as an example and yourconfiguration might be different. For specific configuration of interfaces pointing to SIP trunks and/or athird-party PSTN environment connected to the SBC, see the trunk / environment vendor
documentation.
AudioCodes also offers a comprehensive suite of documents covering the interconnection between
different trunks and equipment.
To configure SIP interfaces:
1.

Open the SIP Interfaces table (Setup menu > Signaling & Media tab > Core Entities folder > SIP
Interfaces).

2.

Configure SIP Interfaces. You can use the default SIP Interface (Index 0), but modify it as shown in
the table below. The table below shows an example of the configuration. You can change someparameters according to your requirements.
The Direct Routing interface can only use TLS for a SIP port. It does not support using TCP due
to security reasons. The SIP port might be any port of your choice. When pairing the SBC with
Office 365, the chosen port is specified in the pairing command.
Table 7: Configuration Example of SIP Signaling Interfaces

Index

Name

0

SIPTrunk(arbitrary
name)

1

Teams
(arbitrary
name)Network
Interface

ApplicationType

UDP Port

LAN_IF

SBC

5060 (according toService Provider
requirement)

WAN_IF

SBC

0(Phone System does
not use UDP or TCP
for SIP signaling)

TLS Port

Enable TCP
Keepalive

Classification
FailureResponse Type

Media
Realm

TLS
Context
Name00

Disable(leavedefault
value)

500 (leave
default value)

MRLan

-

0

5061 (asconfigured in
the Office 365)

Enable0(Recommende
d to prevent
DoS attacks)

MRWan

Teams

TCP
Port

For implementing an MTLS connection with the Microsoft Teams network, configure ‘TLS
Mutual Authentication’ to “Enable” for the Teams SIP Interface.
Loading DigiCert Trusted Root Certificates to AudioCodes' SBC is mandatory for implementing
an MTLS connection with the Microsoft Teams network. Refer to Section 4.5 on page 25.
The configured SIP Interfaces are shown in the figure below:
Figure 28: Configuration Example of SIP Signaling Interfaces- 27 -

4. Configuring AudioCodes' SBC

SBC for Teams DR Enterprise

4.8

Configuring Proxy Sets and Proxy Address

4.8.1

Configuring Proxy Sets
The Proxy Set and Proxy Address defines TLS parameters, IP interfaces, FQDN and the remote entity's
port. Proxy Sets can also be used to configure load balancing between multiple servers. The example
below covers configuration of a Proxy Sets for Teams Direct Routing and SIP Trunk. Note that theconfiguration of a Proxy Set for the SIP Trunk shows as an example and your configuration might bedifferent. For specific configuration of interfaces pointing to SIP trunks and/or the third-party PSTN
environment connected to the SBC, see the trunk/environment vendor's documentation. AudioCodes
also offers a comprehensive suite of documents covering the interconnection between different trunks
and the equipment. The Proxy Sets will later be applied to the VoIP network by assigning them to IP
Groups.
To configure a Proxy Sets:
1.

Open the Proxy Sets table (Setup menu > Signaling & Media tab > Core Entities folder > Proxy
Sets).

2.

Configure Proxy Sets as shown in the table below:
Table 8: Configuration Example Proxy Sets in Proxy Sets Table

Index

Name

SBC IPv4 SIP
Interface

TLS Context
Name

Proxy KeepAlive

Proxy Hot
Swap

Proxy Load
Balancing
Method1

SIPTrunk(arbitrary name)

SIPTrunk

Default

Using Options

-

-

2

Teams
(arbitrary name)

Teams

Teams

Using Options

EnableRandomWeights

The configured Proxy Sets are shown in the figure below:
Figure 29: Configuration Example Proxy Sets in Proxy Sets Table- 28 -

4. Configuring AudioCodes' SBC

4.8.2

SBC for Teams DR Enterprise

Configuring Proxy Addresses
This section shows how to configure a Proxy Address.
To configure a Proxy Address for SIP Trunk:
1.

Open the Proxy Sets table (Setup menu > Signaling & Media tab > Core Entities folder > Proxy
Sets) and then click the Proxy Set SIPTrunk, and then click the Proxy Address link located below
the table; the Proxy Address table opens.

2.

Click +New; the following dialog box appears:
Figure 30: Configuring Proxy Address for SIP Trunk3.

Configure the address of the Proxy Set according to the parameters described in the table below:
Table 9: Configuration Proxy Address for SIP Trunk

Index

Proxy Address

Transport Type

Proxy Priority

Proxy Random Weight

0

SIPTrunk.com:5060(SIP Trunk IP / FQDN and port)

UDP

0

0

4.

Click Apply.

To configure a Proxy Address for Teams:
1.

Open the Proxy Sets table (Setup menu > Signaling & Media tab > Core Entities folder > Proxy
Sets) and then click the Proxy Set Teams, and then click the Proxy Address link located below thetable; the Proxy Address table opens.

2.

Click +New; the following dialog box appears:
Figure 31: Configuring Proxy Address for Teams Direct Routing Interface

3.

Configure the address of the Proxy Set according to the parameters described in the table below:- 29 -

4. Configuring AudioCodes' SBC

SBC for Teams DR Enterprise

Table 10: Configuration Proxy Address for Teams Direct Routing
Index

Proxy Address

Transport Type

Proxy Priority

Proxy Random Weight0

sip.pstnhub.microsoft.com:5061

TLS

1

1

1

sip2.pstnhub.microsoft.com:5061

TLS

2

1

2

sip3.pstnhub.microsoft.com:5061

TLS

3

1

4.

Click Apply and then save your settings to flash memory.
If the SBC is deployed in Office 365 GCC DoD or GCC High environments, please contact
AudioCodes deployment services, since these environments have different configurations(FQDNs) than the public Office 365 environment.

4.9

Configuring Coder Groups
This section describes how to configure coders (known as Coder Groups). Teams Direct Routing supports
the SILK and OPUS coders while the network connection to the SIP Trunk may restrict operation with adedicated coders list. You need to add a Coder Group with the supported coders for each of the following
leg, the Teams Direct Routing and the SIP Trunk.
The Coder Group ID for this entity will be assigned to its corresponding IP Profile in Section
4.10.

To configure a Coder Group:
1.

Open the Coder Groups table (Setup menu > Signaling & Media tab > Coders & Profiles folder >Coder Groups).

2.

From the 'Coder Group Name' dropdown, select 1:Does Not Exist and add the required codecs asshown in the figure below.
Figure 32: Configuring Coder Group for Teams Direct Routing

3.

Click Apply, and then confirm the configuration change in the prompt that pops up.

- 30 -

4. Configuring AudioCodes' SBC

4.10

SBC for Teams DR Enterprise

Configuring IP Profiles
This section describes how to configure IP Profiles. An IP Profile is a set of parameters with user-definedsettings related to signaling (e.g., SIP message terminations such as REFER) and media (e.g., coder type).
An IP Profile needs to be assigned to the specific IP Group.
To configure an IP Profile:1.

Open the Proxy Sets table (Setup menu > Signaling & Media tab > Coders & Profiles folder > IP
Profiles).

2.

Click +New to add the IP Profile for the Direct Routing interface. Configure the parameters using
the table below as reference.
Table 11: Configuration Example: Teams IP Profile
Parameter

Value

GeneralName

Teams (arbitrary descriptive name)Media Security
SBC Media Security Mode

SecuredSBC Early Media
Remote Early Media RTP Detection
Mode

By Media (required, as Teams Direct Routing does not send RTP
immediately to remote side when it sends a SIP 18x response)

SBC Media
Extension Coders Group

AudioCodersGroups_1

RTCP Mode

Generate Always (required, as some ITSPs do not send RTCP
packets during Hold, but Microsoft expects them)

ICE Mode

Lite (required only when Media Bypass enabled on Teams)

SBC Signaling
SIP UPDATE Support

Not Supported

Remote re-INVITE Support

Supported Only With SDP

Remote Delayed Offer Support

Not Supported

SBC Forward and Transfer
Remote REFER Mode

Handle Locally

Remote Replaces Mode

Handle Locally

Remote 3xx Mode

Handle Locally

SBC Hold

Remote Hold Format

Inactive (some SIP Trunk may answer with a=inactive and
IP=0.0.0.0 in response to the Re-Invite with Hold request from
Teams. Microsoft Media Stack doesn’t support this format. So, SBC
will replace 0.0.0.0 with its IP address)
All other parameters can be left unchanged at their default values.

3.

Click Apply, and then save your settings to flash memory.

- 31 -

4. Configuring AudioCodes' SBC

4.

SBC for Teams DR Enterprise

Click +New to add the IP Profile for the SIP Trunk. Configure the parameters using the table below
as a reference.
Table 12: Configuration Example: SIP Trunk IP Profile
Parameter

Value

GeneralName

SIPTrunk

Media Security
SBC Media Security Mode

Not Secured

SBC Signaling
P-Asserted-Identity Header Mode

Add (required for anonymous calls)

SBC Forward and Transfer
Remote REFER Mode

Handle Locally

Remote Replaces Mode

Handle Locally

Play RBT To Transferee

Yes (required, as some SIP Trunks do not play ring-back tone
during transfer)

Remote 3xx Mode

Handle Locally
All other parameters can be left unchanged with their default values.

5.

Click Apply, and then save your settings to flash memory.
Teams Hold music is not supported by Microsoft in consultative transfer of a PSTN call. The
transferee will hear silence during the transfer. To overcome this issue, it is possible toconfigure SBC to play music during a consultative transfer. To do this, refer to Section 4.18.

- 32 -

4. Configuring AudioCodes' SBC

4.11

SBC for Teams DR Enterprise

Configuring IP Groups
This section describes how to configure IP Groups. The IP Group represents an IP entity on the networkwith which the SBC communicates. This can be a server (e.g., IP-PBX or SIP Trunk) or it can be a group ofusers (e.g., LAN IP phones). For servers, the IP Group is typically used to define the server's IP addressby associating it with a Proxy Set. Once IP Groups are configured, they are used to configure IP-to-IP
routing rules for denoting source and destination of the call.
To configure an IP Groups:
1.

Open the IP Groups table (Setup menu > Signaling & Media tab > Core Entities folder > IP
Groups).

2.

Click +New to add the IP Group for the SIP Trunk:
Parameter

Value

Name

SIPTrunk

Type

ServerProxy Set

SIPTrunk

IP Profile

SIPTrunk

Media Realm

MRLan or MRWan (according to your network environment)

SIP Group Name(according to ITSP requirement)

All other parameters can be left unchanged with their default values.
3.

Click +New to add the IP Group for the Teams Direct Routing:Parameter

Value

Name

Teams

Topology Location

Up

Type

ServerProxy Set

Teams

IP Profile

Teams

Media Realm

MRWan

Classify by Proxy Set

DisableLocal Host Name<FQDN name of the SBC in the Enterprise Office 365 tenant>(based on our example, int-sbc1.audctrunk.aceducation.info).

Teams Direct Routing
Mode

Enable (Enables the SBC to include Microsoft's proprietary X-MS-SBC
header in outgoing SIP INVITE and OPTIONS messages in a Microsoft
Teams Direct Routing environment. The header is used by Microsoft
Teams to identify vendor equipment. The header's value is in theformat 'Audiocodes/<model>/<firmware>').

Always Use Src Address

Yes

Outbound Message
Manipulation Set

1

Proxy Keep-Alive using IP
Group settings

EnableAll other parameters can be left unchanged with their default values.
- 33 -

4. Configuring AudioCodes' SBC

SBC for Teams DR Enterprise

The configured IP Groups are shown in the figure below:
Figure 33: Configured IP Groups in IP Group Table

4.12

Configuring SRTP
This section describes how to configure media security. The Direct Routing Interface requires the use of
SRTP only, so you need to configure the SBC to operate in the same manner.
To configure media security:
1.

Open the Media Security page (Setup menu > Signaling & Media tab > Media folder > Media
Security).

2.

From the 'Media Security' drop-down list, select Enable to enable SRTP.
Figure 34: Configuring Media Security Parameter3.

Click Apply.

- 34 -

4. Configuring AudioCodes' SBC

4.13

SBC for Teams DR Enterprise

Configuring Message Manipulation Rules
This section describes how to configure SIP message manipulation rules. SIP message manipulation rules
can include insertion, removal, and/or modification of SIP headers. Manipulation rules are grouped into
Manipulation Sets, enabling you to apply multiple rules to the same SIP message (IP entity).
Once you have configured the SIP message manipulation rules, you need to assign them to the relevant
IP Group (in the IP Group table) and determine whether they must be applied to inbound or outboundmessages.
Implementation of the Message Manipulation rule with Microsoft Teams (shown below) is
optional according to site deployment requirements.

To configure SIP message manipulation rule for Teams:
1.

Open the Message Manipulations page (Setup menu > Signaling & Media tab > Message
Manipulation folder > Message Manipulations).

2.

Configure a new manipulation rule (Manipulation Set 1) for Teams IP Group. This rule applies tomessages sent towards the Teams IP Group. This rule adds a routing policy rule towards
Microsoft for handling different call forwarding scenarios (according to the action values shown
below).
Parameter

Value

Index

0

Name

Teams Routing Policy (arbitrary name)

Manipulation Set ID

1

Condition
Action Subject

header.X-MS-RoutingPolicies

Action Type

Add

Action Value

One of the following values: "none", "no_missed_call","disable_forwarding", "disable_forwarding_except_phone- 35 -

4. Configuring AudioCodes' SBC

4.14

SBC for Teams DR Enterprise

Configuring Message Condition Rules
This section describes how to configure the Message Condition Rules. A Message Condition defines
special conditions (requisites) for incoming SIP messages. These rules can be used as additional matching
criteria for the IP-to-IP routing rules in the IP-to-IP Routing table.
The following condition verifies that the Contact header contains Teams FQDN.
To configure a Message Condition rule:
1.

Open the Message Conditions table (Setup menu > Signaling & Media tab > Message
Manipulation folder > Message Conditions).

2.

Click New, and then configure the parameters as follows:
Parameter

Value

Index

0

Name

Teams-Contact (arbitrary descriptive name)

Condition

header.contact.url.host contains 'pstnhub.microsoft.com'
Figure 35: Configuring Condition Table

3.

Click Apply.

- 36 -

4. Configuring AudioCodes' SBC

4.15

SBC for Teams DR Enterprise

Configuring Classification Rules
This section describes how to configure Classification rules. A Classification rule classifies incoming SIP
dialog-initiating requests (e.g., INVITE messages) to a "source" IP Group. The source IP Group is the SIP
entity that sends the SIP dialog request. Once classified, the device uses the IP Group to process the call(manipulation and routing).
You can also use the Classification table for employing SIP-level access control for successfully classified
calls, by configuring Classification rules with whitelist and blacklist settings. If a Classification rule isconfigured as a whitelist ("Allow"), the device accepts the SIP dialog and processes the call. If theClassification rule is configured as a blacklist ("Deny"), the device rejects the SIP dialog.
To configure a Classification rule:
1.

Open the Classification table (Setup menu > Signaling & Media tab > SBC folder > Classification
Table).

2.

Configure Classification rules as shown in the table below:
Table 13: Classification Rules

Index

Name

SourceSIP
Interface

Source IP
Address

Destination Host

Message
Condition

ActionType

Source IP
Group

0Teams_52_112(arbitrary name)Teams

52.112.*.*

sbc.ACeducation.info(example)

TeamsContact

Allow

Teams

1

Teams_52_113(arbitrary name)Teams

52.113.*.*

sbc.ACeducation.info(example)

TeamsContact

Allow

Teams

2

Teams_52_114(arbitrary name)Teams

52.114.*.*

sbc.ACeducation.info(example)

TeamsContact

Allow

Teams

3

Teams_52_115(arbitrary name)Teams

52.115.*.*

sbc.ACeducation.info(example)

TeamsContact

Allow

Teams

4

Teams_52_122(arbitrary name)Teams

52.122.*.*

sbc.ACeducation.info(example)

TeamsContact

Allow

Teams

5

Teams_52_123(arbitrary name)Teams

52.123.*.*

sbc.ACeducation.info(example)

TeamsContact

Allow

Teams

3.

Click Apply.

- 37 -

4. Configuring AudioCodes' SBC

4.16

SBC for Teams DR Enterprise

Configuring IP-to-IP Call Routing Rules
This section describes how to configure IP-to-IP call routing rules. These rules define the routes forforwarding SIP messages (e.g., INVITE) received from one IP entity to another. The SBC selects the rule
whose configured input characteristics (e.g., IP Group) match those of the incoming SIP message. If the
input characteristics do not match the first rule in the table, they are compared to the second rule, andso on, until a matching rule is located. If no rule is matched, the message is rejected.
The example shown below only covers IP-to-IP routing, though you can route the calls from SIP Trunk toTeams and vice versa. See AudioCodes' SBC documentation for more information on how to route inother scenarios.
The following IP-to-IP Routing Rules will be defined:◼

Terminate SIP OPTIONS messages on the SBC◼

Terminate REFER messages to Teams Direct Routing◼

Calls from Teams Direct Routing to SIP Trunk◼

Calls from SIP Trunk to Teams Direct Routing

To configure IP-to-IP routing rules:
1.

Open the IP-to-IP Routing table (Setup menu > Signaling & Media tab > SBC folder > Routing > IPto-IP Routing).

2.

Configure routing rules as shown in the table below:
Table 14: IP-to-IP Call Routing Rules

Index

Name

Source IP
Group

RequestType

0

Terminate OPTIONSAny

OPTIONS

1

Refer from Teams(arbitrary name)Any2

Teams to SIP Trunk(arbitrary name)3

SIP Trunk to Teams(arbitrary name)Call
Triger

ReRoute IPGroup

Dest TypeDest
IP Group

Dest Address
REFER

Teams

Dest
Address
internal

Request URI

Teams

Teams

IP Group

SIPTrunk

SIPTrunk

IP GroupTeams

The configured routing rules are shown in the figure below:
Figure 36: Configured IP-to-IP Routing Rules in IP-to-IP Routing Table

The routing configuration may change according to your specific deployment topology.

- 38 -

4. Configuring AudioCodes' SBC

4.17

SBC for Teams DR Enterprise

Configuring Firewall Settings
As an extra security, there is option to configure traffic filtering rules (access list) for incoming traffic on
AudioCodes SBC. For each packet received on the configured network interface, the SBC searches thetable from top to bottom until the first matching rule is found. The matched rule can permit (allow) or
deny (block) the packet. Once a rule in the table is located, subsequent rules further down the table are
ignored. If the end of the table is reached without a match, the packet is accepted. Please note that the
firewall is stateless. The blocking rules will apply to all incoming packets, including UDP or TCP responses.
To configure a firewall rule:
1.

Open the Firewall table (Setup menu > IP Network tab > Security folder> Firewall).

2.

Configure the following Access list rules for Teams Direct Rout IP Interface:
Table 15: Firewall Table Rules

Index

Source IP

SubnetPrefix

Start
Port

End
Port

ProtocolUse SpecificInterface

Interface ID

Allow
Type

0

<Public DNS Server
IP>(e.g., 8.8.8.8)

32

0

65535

Any

Enable

WAN_IFAllow

1

52.112.0.0

14

0

65535

TCP

Enable

WAN_IFAllow

2

52.122.0.0

15

0

65535

TCP

Enable

WAN_IF

Allow

3

xxx.xxx.xxx.xxx

32

0

65535

UDP

Enable

WAN_IFAllow

49

0.0.0.0

0

0

65535

Any

Enable

WAN_IFBlock

For information about prerequisites and planning your deployment, refer to Plan Direct
Routing.
Be aware, that if in your configuration, connectivity to SIP Trunk (or other entities) is
performed through the same IP Interface as Teams (WAN_IF in our example), you must add
rules to allow traffic from these entities. See an example in the row of index 3.

- 39 -

4. Configuring AudioCodes' SBC

4.18

SBC for Teams DR Enterprise

Configuring SBC To Play Music On Hold (Optional)
Teams Hold music is not supported by Microsoft in consultative transfer of a PSTN call. The transferee
will hear silence during the transfer. To overcome this issue, it is possible to configure SBC to play music
during a consultative transfer. To do this, a Prerecorded Tones (PRT) file needs to be prepared andloaded to the SBC. This section shows how to load a PRT file to the SBC. For a detailed procedure how
to create Prerecorded Tones (PRT) file, refer to appropriated AudioCodes' device User Manual
document.
Update configuration of the SIP Trunk IP Profile:1.

Open the Proxy Sets table (Setup menu > Signaling & Media tab > Coders & Profiles folder > IP
Profiles).

2.

Choose SIP Trunk IP Profile, created in the Section 4.10 on the page 31. Configure the parameters
using the table below as reference.
Table 16: Update Configuration of the SIP Trunk IP Profile
Parameter

Value

SBC Hold
Remote Hold Format

Send Only

Reliable Held Tone Source

No

Play Held Tone

Internal

3.

Click Apply, and then save your settings to flash memory.

To load PRT file to the device using the Web interface:
1.

Open the Auxiliary Files page:•

Toolbar: From the Actions drop-down menu, choose Auxiliary Files.

•

Navigation tree: Setup menu > Administration tab > Maintenance folder > Auxiliary Files.

2.

Click the Browse button corresponding to the Prerecorded Tones file type that you want to load,
navigate to the folder in which the file is located, and then click Open; the name and path of thefile appear in the field next to the Browse button.

3.

Click the Load File button corresponding to the file you want to load.

4.

Save the loaded auxiliary files to flash memory.
- 40 -

5. Verifying the Pairing Between the SBC and Direct Routing

5

SBC for Teams DR Enterprise

Verifying the Pairing Between the SBC and Direct
Routing
After you have paired the SBC with Direct Routing, validate that the SBC can successfully exchange
OPTIONS with Direct Routing.
To validate the pairing using SIP OPTIONS:
1.

Open the Proxy Set Status page (Monitor menu > VoIP Status tab> Proxy Set Status).

2.

Find the Direct SIP connection and verify that 'Status' is online. If you see a failure, you need totroubleshoot the connection first, before configuring voice routing.
Figure 37: Proxy Set Status- 41 -

6. Making a Test Call

6

SBC for Teams DR Enterprise

Making a Test Call
After installation is complete, you can run a test call from the SBC to a registered user, and in the otherdirection as well. Running a test call will help to perform diagnostics and to check the connectivity for
future support calls or setup automation.
Test calls can be performed using the Test Agent, integral to AudioCodes' SBC. The Test Agent gives you
the ability to remotely verify connectivity, voice quality and SIP message flow between SIP UAs.
A simulated endpoint can be configured on the SBC to test SIP signaling of calls between the SBC and aremote destination. This feature is useful because it can remotely verify SIP message flow without
involving the remote end in the debug process. The SIP test call simulates the SIP signaling process: Call
setup, SIP 1xx responses, through to completing the SIP transaction with a 200 OK.
The test call sends Syslog messages to a Syslog server, showing the SIP message flow, tone signals (e.g.,DTMF), termination reasons, as well as voice quality statistics and thresholds (e.g., MOS).
To configure the Test Agent:
1.

Open the Test Call Rules table (Troubleshooting menu > Troubleshooting tab > Test Call > Test
Call Rules).

2.

Configure a test call according to the parameters of your network. For a detailed description,refer to the AudioCodes User Manual documents.

To start, stop and restart a test call:1.

In the Test Call Rules table, select the required test call entry.

2.

From the Action drop-down list, choose the required command:•

Dial: Starts the test call (applicable only if the test call party is the caller).

•

Drop Call: Stops the test call.

•

Restart: Ends all established calls and then starts the test call session again.

- 42 -

A. Syntax Requirements for SIP Messages 'INVITE' and 'OPTIONS'A

SBC for Teams DR Enterprise

Syntax Requirements for SIP Messages 'INVITE'
and 'OPTIONS'The syntax of SIP messages must conform with Direct Routing requirements.
This section covers the high-level requirements for the SIP syntax used in 'INVITE' and 'OPTIONS'
messages. You can use the information presented here as a first step when troubleshooting unsuccessful
calls. AudioCodes has found that most errors are related to incorrect syntax in SIP messages.

A.1

Terminology
MUST

A.2

Strictly required. The deployment does not function correctly without the correct
configuration of these parameters.

Syntax Requirements for 'INVITE' Messages
Figure 38: Example of an 'INVITE' Message◼

Contact header•

MUST: When placing calls to the Direct Routing interface, the 'CONTACT' header must have
the SBC FQDN in the URI hostname•

Syntax: Contact: <phone number>@<FQDN of the SBC>:<SBC Port>;<transport type>•

If the parameter is not configured correctly, calls are rejected with a '403 Forbidden'
message.

- 43 -

A. Syntax Requirements for SIP Messages 'INVITE' and 'OPTIONS'

A.3

SBC for Teams DR Enterprise

Requirements for 'OPTIONS' Messages Syntax
Figure 39: Example of 'OPTIONS' message◼

Contact header•

MUST: When sending OPTIONS to the Direct Routing interface, the 'CONTACT' header musthave the SBC FQDN in the URI hostname•

Syntax: Contact: <phone number>@<FQDN of the SBC>:<SBC Port>;<transport type>•

If the parameter is not configured correctly, the calls are rejected with a '403 Forbidden'
message

The table below shows where in the Web interface the parameters are configured and where in thisdocument you can find the configuration instructions.
Table 17: Syntax Requirements for an 'OPTIONS' Message
Parameter

Where Configured

How toConfigureContact

Setup > Signaling and Media > Core Entities > IP Groups> <Group Name> >Local Host Name

See Section
4.11.

In IP Group, 'Contact' must be configured. In this field ('Local Host Name'),define the local host name of the SBC as a string, for example, intsbc1.audctrunk.aceducation.info. The name changes the host name in thecall received from the IP Group.

A.4

Connectivity Interface Characteristics
The table below shows the technical characteristics of the Direct Routing interface.
In most cases, Microsoft uses RFC standards as a guide during development, but does not guarantee
interoperability with SBCs - even if they support all the parameters in the table below - due to thespecifics of the implementation of the standards by SBC vendors.
Microsoft has a partnership with some SBC vendors and guarantees their devices' interoperability with
the interface. All validated devices are listed on Microsoft's website. Microsoft only supports devices
that are validated in order to connect to the Direct Routing interface.
AudioCodes is one of the vendors who are in partnership with Microsoft.
AudioCodes' SBCs are validated by Microsoft to connect to the Direct Routing interface.

- 44 -

A. Syntax Requirements for SIP Messages 'INVITE' and 'OPTIONS'

SBC for Teams DR Enterprise

Table 18: Teams Direct Routing Interface - Technical Characteristics
Category

ParameterPorts and IP
rangesSIP Interface FQDN Name

See Microsoft's document
Deploying Direct Routing Guide.

-

IP Addresses range for SIP
interfaces

See Microsoft's document
Deploying Direct Routing Guide.

-

SIP Port

5061-

IP Address range forMedia

See Microsoft's document
Deploying Direct Routing Guide.

-Media port range on
Media Processors

See Microsoft's document
Deploying Direct Routing Guide.

-Media Port range on theclientSee Microsoft's document
Deploying Direct Routing Guide.

-

SIP transport

TLS-

Media Transport

SRTP

-

SRTP Security Context

DTLS, SIPS

Transport
and Security

Value

Note: Support for DTLS is pending.
Currently, SIPS must be configured.
When support for DTLS will beannounced, it will be therecommended context.

https://tools.ietf.org/ht
ml/rfc5763

Crypto Suite

AES_CM_128_HMAC_SHA1_80,
non-MKI-

Control protocol for media
transport

SRTCP (SRTCP-Mux recommended)

Using RTCP MUX helps
reduce the number ofrequired ports

Supported Certification
Authorities

See the Deployment Guide

Transport for Media
Bypass (of configured)◼

Audio codecs

◼

◼
◼
◼
◼

CodecsComments

Other codecs

◼
◼
◼
◼
◼
◼

ICE-lite (RFC5245) –recommended
Client also has Transport Relays
G711
Silk (Teams clients)
Opus (WebRTC clients) - only if
Media Bypass is used
G729
CN
Required narrowband andwidebandRED - Not required
DTMF - Required
Events 0-16
Silence Suppression - Not
required- 45 ----

B. SIP Proxy Direct Routing Requirements

B

SBC for Teams DR Enterprise

SIP Proxy Direct Routing Requirements
Teams Direct Routing has three FQDNs:◼

sip.pstnhub.microsoft.com [Global FQDN. The SBC attempts to use it as the first priority region.
When the SBC sends a request to resolve this name, the Microsoft Azure DNS server returns an IP
address pointing to the primary Azure datacenter assigned to the SBC. The assignment is basedon performance metrics of the datacenters and geographical proximity to the SBC. The IP address
returned corresponds to the primary FQDN.]◼

sip2.pstnhub.microsoft.com [Secondary FQDN. Geographically maps to the second priority
region.]◼

sip3.pstnhub.microsoft.com [Tertiary FQDN. Geographically maps to the third priority region.]

These three FQDNs must be placed in the order shown above to provide optimal quality of experience(less loaded and closest to the SBC datacenter assigned by querying the first FQDN).
The three FQDNs provide a failover if a connection is established from an SBC to a datacenter that is
experiencing a temporary issue.

B.1

Failover Mechanism
The SBC queries the DNS server to resolve sip.pstnhub.microsoft.com. The primary datacenter isselected based on geographical proximity and datacenters performance metrics.
If during the connection the primary datacenter experiences an issue, the SBC will attempt
sip2.pstnhub.microsoft.com which resolves to the second assigned datacenter, and in rare cases if
datacenters in two regions are unavailable, the SBC retries the last FQDN (sip3.pstnhub.microsoft.com)
which provides the tertiary datacenter IP address.
The SBC must send SIP OPTIONS to all IP addresses that are resolved from the three FQDNs, that is,
sip.pstnhub.microsoft.com, sip2.pstnhub.microsoft.com and sip3.pstnhub.microsoft.com.

- 46 -

International Headquarters
1 Hayarden Street,
Airport City
Lod 7019900, Israel
Tel: +972-3-976-4000
Fax: +972-3-976-4040
AudioCodes Inc.
80 Kingsbridge Rd
Piscataway, NJ 08854, USA
Tel: +1-732-469-0880
Fax: +1-732-469-2298

Contact us: https://www.audiocodes.com/corporate/offices-worldwide
Website: https://www.audiocodes.com©2023 AudioCodes Ltd. All rights reserved. AudioCodes, AC, HD VoIP, HD VoIP Sounds Better, IPmedia,
Mediant, MediaPack, What’s Inside Matters, OSN, SmartTAP, User Management Pack, VMAS, VoIPerfect,
VoIPerfectHD, Your Gateway To VoIP, 3GX, VocaNom, AudioCodes One Voice, AudioCodes Meeting
Insights, and AudioCodes Room Experience are trademarks or registered trademarks of AudioCodes
Limited. All other products or trademarks are property of their respective owners. Product specifications
are subject to change without notice.

Document #: LTRT-13339