Connecting AudioCodes' SBC to Microsoft Azure Communication

Mediant SBC with Microsoft Azure Commun ication Services

Configuration Note

AudioCodes Mediant™ Family of Media Gateways & Session Border Controllers

Connecting AudioCodes' SBC to

Microsoft Azure Communication

Services

Contents 
AudioCodes SBC 
 
- ii - 
Table of Contents 
Mediant SBC with Microsoft Azure Communication Services ...............................................1 
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 ............................................................................................................... v 
1  Introduction .................................................................................................................6 
1.1  About Microsoft Azure Communication Services ................................................................. 6 
1.2  About AudioCodes SBC Product Series ................................................................................. 6 
1.3  Validated AudioCodes Version ............................................................................................. 7 
2  Topology Example ........................................................................................................8 
2.1  Environment Setup ............................................................................................................... 9 
2.2  Infrastructure Prerequisites.................................................................................................. 9 
3  Configuring Azure Communication Services direct routing .......................................... 10 
4  Deploying Mediant VE Via Azure Marketplace ............................................................ 11 
5  Configuring AudioCodes' SBC ...................................................................................... 18 
5.1  SBC Configuration Concept with ACS .................................................................................. 18 
5.2  IP Network Interfaces Configuration .................................................................................. 19 
5.2.1  Configure VLANs .............................................................................................................. 20 
5.2.2  Configure Network Interfaces .......................................................................................... 20 
5.2.3  Configure NAT Translation................................................................................................ 20 
5.3  SIP TLS Connection Configuration....................................................................................... 21 
5.3.1  Configure the NTP Server Address .................................................................................... 21 
5.3.2  Create a TLS Context for ACS (same as for Teams Direct Routing) .................................... 22 
5.3.3  Generate a CSR and Obtain the Certificate from a Supported CA ..................................... 23 
5.3.4  Deploy the SBC and Root / Intermediate Certificates on the SBC ...................................... 25 
5.3.5  Method of Generating and Installing the Wildcard Certificate .......................................... 27 
5.3.6  Deploy Trusted Root Certificate for MTLS Connection ...................................................... 27 
5.4  Configure Media Realm ...................................................................................................... 28 
5.5  Configure SIP Signaling Interfaces ...................................................................................... 29 
5.6  Configure Proxy Sets and Proxy Address ............................................................................ 30 
5.6.1  Configure Proxy Sets ........................................................................................................ 30 
5.6.2  Configure Proxy Addresses ............................................................................................... 31 
5.7  Configure Coder Groups ..................................................................................................... 33 

Contents 
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5.8  Configure IP Profiles ........................................................................................................... 34 
5.9  Configure IP Groups ............................................................................................................ 36 
5.10  Configure SRTP ................................................................................................................... 38 
5.11  Configure Message Manipulation Rules ............................................................................. 39 
5.12  Configure Message Condition Rules ................................................................................... 40 
5.13  Configure Classification Rules ............................................................................................. 41 
5.14  Configure IP-to-IP Call Routing Rules .................................................................................. 42 
5.15  Configure Number Manipulation Rules .............................................................................. 43 
5.16  Miscellaneous Configuration .............................................................................................. 44 
5.16.1  Optimizing CPU Cores Usage for a Specific Service (relevant for Mediant 9000 and 
Software SBC only) ......................................................................................................................... 44 
6  Verify the Pairing Between the SBC and ACS ............................................................... 45 
A  Syntax Requirements for SIP Messages 'INVITE' and 'OPTIONS' .................................. 46 
A.1  Terminology........................................................................................................................ 46 
A.2  Syntax Requirements for 'INVITE' Messages ...................................................................... 46 
A.3  Requirements for 'OPTIONS' Messages Syntax................................................................... 46 
A.4  Connectivity Interface Characteristics ................................................................................ 48 
B  SIP Proxy Direct Routing Requirements ...................................................................... 49 
B.1  Failover Mechanism ........................................................................................................... 49 
 

Notices

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Notice

Information contained in this document is believed to be accurate and reliable at the time of

printing. However, due to ongoing product improvements and revisions, AudioCodes cannot

guarantee accuracy of printed material after the Date Published nor can it accept responsibility for

errors or omissions. Updates to this document can be downloaded from

https://www.audiocodes.com/library/technical-documents.

This document is subject to change without notice.

Date Published: January-05-2023

WEEE EU Directive

Pursuant to the WEEE EU Directive, electronic and electrical waste must not be disposed of with

unsorted 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 and for contact information, please visit our website at

https://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.

Notices

AudioCodes SBC

- v -

Related Documentation

Document Name

Mediant 500 Gateway & E-SBC User's Manual

Mediant 500L Gateway & E-SBC User's Manual

Mediant 800 Gateway & E-SBC User's Manual

Mediant 1000B Gateway & E-SBC User's Manual

Mediant 2600 SBC User's Manual

Mediant 4000 SBC User's Manual

Mediant 9000 SBC User's Manual

Mediant Software SBC User's Manual

Gateway and SBC CLI Reference Guide

SIP Message Manipulation Reference Guide

AudioCodes Configuration Notes

Document Revision Record

47BLTRT

Description

39470

Initial document release

39471

Change "ACS SIP interface" to "Azure Communication Services direct routing" per

Microsoft request and add links to Microsoft docs in Section 3

39472

Minor fixes per Microsoft request

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 form

on our website at https://online.audiocodes.com/documentation-feedback.

1. Introduction

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1 Introduction

This document describes how to connect AudioCodes' SBC to the Microsoft Azure Communication

Services (ACS) and refers to the AudioCodes SBC configuration only. For more information about

Microsoft Azure Communication Services, please refer to https://docs.microsoft.com/en-

us/azure/communication-services/.

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 Azure Communication Services

Azure Communication Services allows you to easily add real-time voice, video, and telephone

communication to your applications. Communication Services SDKs also allow you to add SMS

functionality to your communications solutions. Azure Communication Services is identity agnostic;

you have complete control over how end users are identified and authenticated. You can connect

people to the communication data plane or services (bots).

Applications include:

◼ Business to Consumer (B2C). Business employees and services can interact with consumers

using voice, video, and rich text chat in a custom browser or mobile application. An

organization can send and receive SMS messages or operate an interactive voice response

system (IVR) using a phone number acquired through Azure. Integration with Microsoft Teams

allows consumers to join Teams meetings hosted by employees; ideal for remote healthcare,

banking, and product support scenarios where employees might already be familiar with

Teams.

◼ Consumer to Consumer. Build engaging social spaces for consumer-to-consumer interaction

with voice, video, and rich text chat. Any type of user interface can be built on Azure

Communication Services SDKs. Complete application samples and UI assets are available to

help you get started quickly.

1.2 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

with a native host processor, allowing the creation of purpose-built multiservice appliances,

providing smooth connectivity to cloud services, with integrated quality of service, SLA monitoring,

security and manageability. The native implementation of SBC provides a host of additional

capabilities that are not possible with standalone SBC appliances such as VoIP mediation, PSTN access

survivability, and third-party 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. Introduction

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1.3 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 Azure Communication Services based on the configuration

described in this document, AudioCodes SBC must be installed with a License Key that

includes the following 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. Topology Example

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2 Topology Example

ACS PSTN Telephony Voice Calling allow users to interact with a traditional telephone number,

facilitated by PSTN (Public Switched Telephone Network) for voice calling. ACS supports a “SIP

Interface”. This allows you to connect, via a certified SBC, PBXs, Analog Telephony Adapters, or

another PSTN carrier.

Figure 1: Azure Communication Services direct routing

Figure 2: Interoperability Test Topology

Internet

SIP TRUNK

ITSP

Management

Station (OAMP)

Enterprise Network

LAN

PSTN

Firewall

Mobile App

User

Web App

User

Session Border Controller

Azure

Communication

Services

This document shows how to configure the connection between AudioCodes' SBC and the

Microsoft Azure Communication Services (ACS) with a generic SIP Trunk. For detailed

configuration of other entities 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).

2. Topology Example

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2.1 Environment Setup

The topology example includes the following environment setup:

Table 1: Environment Setup

Area

Setup

Network

◼ Both, Company SIP Trunk and ACS environment, are located on the

Enterprise's (or Service Provider’s) WAN

Signaling

Transcoding

◼ ACS operates with SIP-over-TLS transport type

◼ Generic SIP Trunk operates with SIP-over-UDP transport type

Codecs Transcoding

◼ ACS supports G.711A-law, G.711U-law, G.722, G.729 and SILK (NB

and WB) coders

◼ Generic SIP Trunk supports G.711A-law, G.711U-law, and G.729

coders

Media Transcoding

◼ ACS operates with SRTP media type

◼ Generic SIP Trunk operates with RTP media type

2.2 Infrastructure Prerequisites

The table below shows the list of infrastructure prerequisites required for deploying connection to

Azure Communication Services. These are the same requirement as for interconnect with Teams

Direct Routing.

Table 2-2: Infrastructure Prerequisites

Infrastructure Prerequisite

Details

Certified Session Border Controller (SBC)

See Microsoft's document Plan Direct Routing.

SIP Trunks connected to the SBC

Azure Communication resource

Domains

Public IP address for the SBC

Fully Qualified Domain Name (FQDN) for the SBC

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 Media

Media Transport Profile

Firewall ports for ACS Clients Media

3. Configuring Azure Communication Services direct routing

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3 Configuring Azure Communication Services

direct routing

Currently, a configuration description of the Microsoft Azure Communication Services direct routing

is not available, it will be added in the future. The following links can be used to start working with

the SIP Interface for interconnect to Microsoft Azure Communication Services:

◼ About Direct Routing

◼ Azure direct routing infrastructure requirements

◼ Provision SBC and configure voice routing

◼ What is Azure Communication Services

◼ How to create an ACS resource

◼ Build your own app quickstart

◼ Web app with calling capabilities

4. Deploying Mediant VE Via Azure Marketplace

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4 Deploying Mediant VE Via Azure Marketplace

This section describes the deployment of a standalone Mediant VE through the Azure Marketplace.

This deployment method uses a graphical user interface and is therefore, most suited if you are not

familiar with the Azure cloud environment.

To deploy a standalone Mediant VE through Azure Marketplace:

1. Open the Azure Marketplace at https://azuremarketplace.microsoft.com/.

2. Search for the product "Mediant VE Session Border Controller (SBC)" published by

AudioCodes.

Figure 3: Azure Marketplace

3. Click GET IT NOW; the Azure portal and Mediant VE SBC Product Overview screen appears:

Figure 4: Mediant VE SBC Product Overview

4. Deploying Mediant VE Via Azure Marketplace

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4. Click Create to start a new Mediant VE deployment.

The Create AudioCodes Mediant VE SBC for Microsoft Azure dialog appears. The dialog

contains multiple steps. Complete each step according to the description below.

Figure 5: Basics Step

5. In the Basics step, do the following:

a. In the ‘Subscription’ field, select a proper subscription for your deployment.

b. In the ‘Resource group’ field, click Create new and then enter a unique name for the new

resource group. Alternatively, you may select an existing empty resource group from the

list.

c. In the ‘Region’ field, select a proper region for your deployment.

d. In the 'Virtual Machine name' field, enter a unique name for the new VM.

e. In the 'Username' field, enter a username.

f. For 'Authentication type', select Password.

g. In the 'Password' field, enter a password, and then enter it again in the ‘Confirm

password’ field.

4. Deploying Mediant VE Via Azure Marketplace

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These credentials are used to connect to the management interface of the deployed

Mediant VE (instead of the default Admin/Admin credentials used in other

environments).

Azure imposes some limitations on username and password. For example, it prohibits the

use of "Admin" for username and requires you to use a strong password that meets the

following policy:

◼ A minimum of 12 characters

◼ Use three out of the following characters:

• lowercase characters

• uppercase characters

• numbers

• symbols

h. Click OK.

6. In the Virtual Machine Settings step, do the following:

a. Choose the virtual machine size.

For a list of supported virtual machine sizes and corresponding capacity figures, refer to

the SBC-Gateway-MSBR Series Release Notes.

b. Choose the disk type for the virtual machine.

As SBC software typically doesn’t perform extensive disk activity, Standard HDD disk type

is adequate for most deployments. However, if you plan to use SBC for transcoding, then

a virtual machine should have a minimum of 2 vCPUs.

c. Choose the OS version for the deployed SBC software:

 6 – this version corresponds to the 7.20A stream, which is based on CentOS 6.

 8 – this version corresponds to the new 7.40A stream, which is based on CentOS

Stream 8 and provides significantly better performance and capacity (refer to the

SBC-Gateway Series Release Notes for details).

d. Choose whether to enable virtual machine’s boot diagnostics.

e. (Optionally), provide Mediant VE automatic configuration script (cloud-init file).

For more information, refer to the Automatic Provisioning of Mediant VE SBC via Cloud-

Init Configuration Note.

f. Click OK.

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Figure 6: Virtual Machine Settings Step

7. In the Network Settings step, do the following:

a. Choose the number of network interfaces for the new virtual machine.

Deployment via Azure Marketplace supports up to two network interfaces. If you need

more interfaces, perform deployment via the PowerShell CLI, as described in the

Mediant Virtual Edition SBC for Microsoft Azure Installation Manual.

b. Configure the virtual network where the new VM will be deployed.

You may either create a new virtual network or select an existing one. Azure virtual

machine is always connected to a single virtual network, regardless of the number of its

network interfaces.

c. Configure the subnet for each network interface.

You may either create a new subnet (for new virtual network) or select an existing one.

If you choose two network interfaces, you must connect each interface to a different

subnet. This is a limitation of Azure Marketplace UI and may be overcome by performing

the deployment via the PowerShell CLI, as described in the Mediant Virtual Edition SBC

for Microsoft Azure Installation Manual. You can then access the SBC management

interfaces (Web and SSH) through the 1

network interface only.

d. Configure the virtual machine’s Public IP Address.

You may either create a new Public IP Address or select an existing one.

 If you create a new Public IP Address, select Static Assignment. This ensures that

the IP address remains unchanged if you stop the virtual machine.

 If you choose two network interfaces, the public IP address will be attached to the

network interface.

e. Click OK

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Figure 7: Network Settings Step

8. In the Review + create step, review the Mediant VE SBC terms of use and virtual machine

configuration, and then click Create.

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Figure 8: Review + Create Step

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9. Wait until the virtual machine deployment is complete, and then determine the IP address

that is assigned to your virtual machine that can be used to access management interface:

 If you assigned a public IP address to the VM, you may use it to access the

management interface.

 Alternatively, you may use a private IP address of the 1

network interface.

Figure 9: Determining IP Address of Deployed VM

10. Log in to the management interface (through Web or SSH) using the credentials that you

configured during the virtual machine set up.

5. Configuring AudioCodes' SBC

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5 Configuring AudioCodes' SBC

This section provides example of step-by-step procedures on how to configure AudioCodes SBC for

interworking between Microsoft Azure Communication Services (ACS) and the Generic SIP Trunk.

These configuration procedures are based on the topology example described in Section 2.1

on page 9, and includes the following main topics:

◼ SBC LAN interface – administrator's management station and Generic SIP Trunking (depend on

topology) environment

◼ SBC WAN interface - Generic 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).

◼ For implementing connection to ACS based on the configuration described in this

section, AudioCodes SBC must be installed with a License Key. For more information,

see Section 1.3 on page 7.

◼ The scope of this document does not cover all security aspects for configuring this

topology. Comprehensive security measures should be implemented per your

organization's security policies. For security recommendations on AudioCodes’

products, refer to the Recommended Security Guidelines document, which can be

found at AudioCodes web site.

5.1 SBC Configuration Concept with ACS

The diagram below represents AudioCodes’ device configuration concept.

Figure 10: SBC Configuration Concept

SIP

Trunk

Proxy Set IP Group

SIP

Interface

SIP

Interface

IP Group Proxy Set

SBC

Azure

Communication

Services

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5.2 IP 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:

• ACS - 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

to the 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 11: Network Interfaces in the Topology with SIP Trunk on the LAN

Management

Station (OAMP)

ITSP

LAN

WAN

DMZ

LAN Port

Vlan ID 1

Vlan ID 2

Session Border Controller

Firewall

Azure

Communication

Services

Figure 12: Network Interfaces in the Topology with SIP Trunk on the WAN

ITSP

Management

Station (OAMP)

LAN

WAN

DMZ

LAN Port

Vlan ID 1

Vlan ID 2

Session Border Controller

Firewall

Azure

Communication

Services

This document provides an example of the following deployment method:

◼ SBC implemented in the Azure with one IP interface, used for all purposes:

• Management (OAMP)

• Signaling and media connectivity to Generic SIP Trunk and ACS

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5.2.1 Configure VLANs

Since default VLANs configuration was used in this interoperability test topology, no additional

configuration is needed.

5.2.2 Configure Network Interfaces

Network Interfaces are configured automatically in the Azure implementation. Refer to the Mediant

Virtual Edition SBC for Microsoft Azure Installation Manual document, which can be found at

AudioCodes web site. The example of the configured IP network interface are shown below:

Figure 13: Configuration Example of the Network Interface Table

5.2.3 Configure NAT Translation

The SBC, located in the Azure Cloud, implements private IP addresses. The NAT Translation table lets

you configure network address translation (NAT) rules for translating source IP addresses into NAT

IP addresses (global - public). These are used in front of the Azure firewall facing the Generic SIP

Trunk and the ACS.

A NAT Translation Table is created automatically during the implementation process (as described in

step 7 on page 14 above.) But if it is required to configure manually, follow next steps.

To configure the NAT translation rules:

1. Open the NAT Translation table (Setup menu > IP Network tab > Core Entities folder > NAT

Translation).

2. Add a new NAT Translation rule by clicking +New at the top of the interface, and then

configure the parameters using the table below as reference.

Table 3: NAT Translation Rule

Index

Source

Interface

Source Start

Port

Source End

Port

Target IP Address

Target Start

Port

Target End

Port

eth0

65535

65535

3. Click Apply.

Figure 14: Example of the NAT Translation Table

5. Configuring AudioCodes' SBC

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5.3 SIP TLS Connection Configuration

This section describes how to configure the SBC for using a TLS connection with the ACS. 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: acstest.audiocodes.be

◼ SAN: acstest.audiocodes.be

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 Azure Communication Services direct routing allows only TLS connections from SBCs for SIP

traffic with a certificate 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-

for-the-sbc

5.3.1 Configure the NTP Server Address

This 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., time.windows.com).

Figure 15: Configuring NTP Server Address

3. Click Apply.

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5.3.2 Create a TLS Context for ACS (same as 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 SSL.com Global Root CA. The certificate is used by the SBC to authenticate

the connection with ACS.

The procedure involves the following main steps:

a. Create a TLS Context for ACS

b. Generate a Certificate Signing Request (CSR) and obtain the certificate from a supported

Certification Authority

c. Deploy the SBC and Root / Intermediate certificates on the SBC

To create a TLS Context for ACS:

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 the

parameters using the table below as reference.

Table 4: New TLS Context

Index

Name

TLS Version

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. You

might 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

information on the SBC's configuration, see the User's Manual, available for download from

https://www.audiocodes.com/library/technical-documents.

Figure 16: Configuration of TLS Context for ACS

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3. Click Apply; you should see the new TLS Context and option to manage the certificates at the

bottom of 'TLS Context' table.

Figure 17: Configured TLS Context for ACS and Interface to

Manage the Certificates

5.3.3 Generate a CSR and Obtain 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,

acstest.audiocodes.be).

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, acstest.audiocodes.be).

c. Change the 'Private Key Size' based on the requirements of your Certification Authority.

Many CAs do not support private key of size 1024.

d. To change the key size on TLS Context, go to: Generate New Private Key and Self-Signed

Certificate, change the 'Private Key Size' to 1024 (if this required by CA) and then click

Generate Private-Key. To use 2048 as a Private Key Size value, you can click Generate

Private-Key without changing the default key size value.

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

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f. Click the Create CSR button; a textual certificate signing request is displayed in the area

below the button:

Figure 18: 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,

for example certreq.txt.

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

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5.3.4 Deploy the SBC and Root / Intermediate Certificates on the SBC

After obtaining the SBC signed and Trusted Root/Intermediate Certificate from the CA, install the

following:

◼ 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

File button corresponding to the 'Send Device Certificate...' field, navigate to the

certificate file obtained from the CA, and then click Load File to upload the certificate to

the SBC.

Figure 19: 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 20: Message Indicating Successful Upload of the Certificate

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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:

Figure 21: Certificate Information Example

4. 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 the

Trusted 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 from

your Certification Authority to load.

5. Click OK; the certificate is loaded to the device and listed in the Trusted Certificates store:

Figure 22: Example of Configured Trusted Root Certificates

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5.3.5 Method of Generating and Installing the Wildcard Certificate

To use the same certificate on multiple devices, you may prefer using 3

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:

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

pass-phrase' field.

b. Click the Choose File button corresponding to the 'Send Private Key...' field and then

select the SBC certificate file exported from the DigiCert utility.

5.3.6 Deploy Trusted Root Certificate for MTLS Connection

Loading Trusted Root Certificates to AudioCodes' SBC is mandatory for implementing an

MTLS connection with the Microsoft Teams network.

Microsoft 365 updated services such as, messaging, meetings, telephony, voice, and video

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.

The DNS name of the Teams Direct Routing interface is sip.pstnhub.microsoft.com. In this interface,

a certificate is presented which is signed by DigiCert with:

Serial Number: 0x033af1e6a711a9a0bb2864b11d09fae5,

SHA-1 Thumbprint: DF3C24F9BFD666761B268073FE06D1CC8D4F82A4 and

SHA-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 from

https://www.digicert.com/kb/digicert-root-certificates.htm and follow the steps above to import

the certificate 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'.

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5.4 Configure Media Realm

Media Realms allow dividing the UDP port ranges for use on different interfaces. In the example

below, two Media Realms are configured:

◼ One for the WAN 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 5: Configuration Example Media Realms in Media Realm Table

Index

Name

Topology

Location

IPv4 Interface

Name

Port Range

Start

Number of Media Session

Legs

MR-ACS

(arbitrary name)

eth0

6000

100 (media sessions assigned

with port range)

MR-SIPTrunk

(arbitrary name)

eth0

7000

100 (media sessions assigned

with port range)

The configured Media Realms are shown in the figure below:

Figure 23: Configuration Example Media Realms in Media Realm Table

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5.5 Configure 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

(configured in the Interface Table above) and Media Realm.

Note that the configuration of a SIP interface for the SIP Trunk shows as an example and your

configuration might be different. For specific configuration of interfaces pointing to SIP trunks and/or

a third-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 some parameters according to your requirements.

The Azure Communication Services direct routing 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.

Table 6: Configuration Example of SIP Signaling Interfaces

Index

Name

Network

Interface

Application

Type

UDP Port

TCP

Port

TLS Port

Enable TCP

Keepalive

Classification

Failure Response

Type

Media Realm

TLS

Context

Name

SI-ACS

(arbitrary

name)

eth0

SBC

0 (Phone System

does not use UDP or

TCP for SIP signaling)

5061

(as configured in

the Office 365)

Enable

0 (Recommended

to prevent DoS

attacks)

MR-ACS

Teams

SI-SIPTrunk

(arbitrary

name)

eth0

SBC

5060 (according to

Service Provider

requirement)

Disable (leave

default value)

0 (Recommended

to prevent DoS

attacks)

MR-SIPTrunk

For implementing an MTLS connection with the Microsoft Teams network, configure ‘TLS

Mutual Authentication’ to “Enable” for the Azure Communication Services direct routing.

Loading DigiCert Trusted Root Certificates to AudioCodes' SBC is mandatory for

implementing an MTLS connection with the Microsoft Teams network. Refer to Section

5.3.6 on page 27.

The configured SIP Interfaces are shown in the figure below:

Figure 24: Configuration Example of SIP Signaling Interfaces

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5.6 Configure Proxy Sets and Proxy Address

5.6.1 Configure 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 ACS and SIP Trunk. Note that the configuration of a

Proxy Set for the SIP Trunk shows as an example and your configuration might be different. 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.

For devices with PSTN interface (Hybrid SBC) it is highly recommended that you do not

configure Proxy Set ID 0 and IP Group ID 0. The only time that you should configure this

specific Proxy Set and IP Group is when it is used for the Gateway Interface (e.g., PSTN

fallback).

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 7: Configuration Example Proxy Sets in Proxy Sets Table

Index

Name

SBC IPv4

SIP

Interface

TLS Context

Name

Proxy Keep-

Alive

Proxy Hot

Swap

Proxy Load

Balancing

Method

PS-ACS

(arbitrary name)

SI-ACS

Teams

Using Options

Enable

Random

Weights

PS-SIPTrunk

(arbitrary name)

SI-SIPTrunk

Default

Using Options

The configured Proxy Sets are shown in the figure below:

Figure 25: Configuration Example Proxy Sets in Proxy Sets Table

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5.6.2 Configure Proxy Addresses

This section shows how to configure a Proxy Address.

To configure a Proxy Address for ACS (same as for Teams Direct Routing):

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

Sets) and then click the Proxy Set PS-ACS, 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 26: Configuring Proxy Address for Azure Communication Services direct routing

3. Configure the address of the Proxy Set according to the parameters described in the table

below:

Table 8: Configuration Proxy Address for ACS

Index

Proxy Address

Transport

Type

Proxy

Priority

Proxy Random

Weight

sip.pstnhub.microsoft.com:5061

TLS

sip2.pstnhub.microsoft.com:5061

TLS

sip3.pstnhub.microsoft.com:5061

TLS

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

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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 27: Configuring Proxy Address for SIP Trunk

3. 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

SIPTrunk.com:5060

(SIP Trunk IP / FQDN and port)

UDP

4. Click Apply.

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5.7 Configure Coder Groups

This section describes how to configure coders (known as Coder Groups). ACS supports the SILK and

G.722 coders while the network connection to the SIP Trunk may restrict operation with a dedicated

coders list. You need to add a Coder Group with the supported coders for each of the following leg,

the ACS and the SIP Trunk.

The Coder Group ID for this entity will be assigned to its corresponding IP Profile in

Section 5.8.

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

as shown in the figure below.

Figure 28: Configuring Coder Group for ACS

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

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5.8 Configure IP Profiles

This section describes how to configure IP Profiles. An IP Profile is a set of parameters with user-

defined settings 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 and Media tab > Coders and Profiles

folder > IP Profiles).

2. Click +New to add the IP Profile for the Azure Communication Services direct routing.

Configure the parameters using the table below as reference.

Table 10: Configuration Example: ACS IP Profile

Parameter

Value

General

Name

ACS (arbitrary descriptive name)

Media Security

SBC Media Security Mode

Secured

SBC 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

RFC 2833 Mode

Extended

RTCP Mode

Generate Always (required, as some ITSPs do not send RTCP

packets during Hold, but Microsoft expects them)

ICE Mode

Lite

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.

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4. Click +New to add the IP Profile for the SIP Trunk. Configure the parameters using the table

below as a reference.

Table 11: Configuration Example: SIP Trunk IP Profile

Parameter

Value

General

Name

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

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.

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5.9 Configure IP Groups

This section describes how to configure IP Groups. The IP Group represents an IP entity on the

network with which the SBC communicates. This can be a server (e.g., IP-PBX or SIP Trunk) or it can

be a group of users (e.g., LAN IP phones). For servers, the IP Group is typically used to define the

server's IP address by 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.

For devices with PSTN interface (Hybrid SBC) it is highly recommended that you do not

configure Proxy Set ID 0 and IP Group ID 0. The only time that you should configure this

specific Proxy Set and IP Group is when it is used for the Gateway Interface (e.g., PSTN

fallback).

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 ACS:

Parameter

Value

Name

IPG-ACS

Topology Location

Type

Server

Proxy Set

PS-ACS

IP Profile

ACS

Media Realm

MR-ACS

Classify by Proxy Set

Disable

Local Host Name

(based on our example, acstest.audiocodes.be).

Always Use Src Address

Yes

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 the format 'Audiocodes/<model>/<firmware>').

Inbound Message

Manipulation Set

Proxy Keep-Alive using IP

Group settings

Enable

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

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

Parameter

Value

Name

IPG-SIPTrunk

Type

Server

Proxy Set

PS-SIPTrunk

IP Profile

SIPTrunk

Media Realm

MR-SIPTrunk

SIP Group Name

(according to ITSP requirement)

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

The configuration of the SIP Trunk example and your configuration might be different. For

specific configuration of interfaces pointing to SIP trunks and/or a third-party PSTN

environment connected to the SBC, see the trunk / environment vendor documentation.

The configured IP Groups are shown in the figure below:

Figure 29: Configured IP Groups in IP Group Table

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5.10 Configure SRTP

This section describes how to configure media security. The Azure Communication Services direct

routing 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 30: Configuring Media Security Parameter

3. Click Apply.

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5.11 Configure 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

outbound messages.

Implementation of the Message Manipulation rule with ACS (shown below) is optional

according to site deployment requirements.

To configure SIP message manipulation rule for ACS:

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 ACS. This rule applies to messages

received from the ACS IP Group. This rule removes the SIP P-Asserted-Identity header.

Parameter

Value

Index

Name

Remove PAI

Manipulation Set ID

Action Subject

Header.P-Asserted-Identity

Action Type

Remove

3. Configure another manipulation rule (Manipulation Set 1) for ACS. This rule applies to

messages received from the ACS IP Group. This rule remove the SIP Privacy Header in all

messages, except for calls with presentation restriction.

Parameter

Value

Index

Name

Remove Privacy Header

Manipulation Set ID

Condition

Header.Privacy exists And Header.From.URL !contains

'anonymous'

Action Subject

Header.Privacy

Action Type

Remove

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5.12 Configure 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 Microsoft 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

Name

MSFT-Contact (arbitrary descriptive name)

Condition

Header.Contact.URL.Host contains 'pstnhub.microsoft.com'

Figure 31: Configuring Condition Table

3. Click Apply.

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5.13 Configure 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 is configured as a whitelist ("Allow"), the device accepts the SIP dialog and

processes the call. If the Classification 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 5-12: Classification Rules

Index

Name

Source

SIP Interface

Source

IP Address

Destination Host

Message

Condition

Action

Type

Source

IP Group

Teams_52_112

(arbitrary name)

SI-ACS

52.112.*.*

acstest.audiocodes.be

(example)

MSFT-

Contact

Allow

IPG-ACS

Teams_52_113

(arbitrary name)

SI-ACS

52.113.*.*

acstest.audiocodes.be

(example)

MSFT-

Contact

Allow

IPG-ACS

Teams_52_114

(arbitrary name)

SI-ACS

52.114.*.*

acstest.audiocodes.be

(example)

MSFT-

Contact

Allow

IPG-ACS

Teams_52_115

(arbitrary name)

SI-ACS

52.115.*.*

acstest.audiocodes.be

(example)

MSFT-

Contact

Allow

IPG-ACS

Teams_52_120

(arbitrary name)

SI-ACS

52.120.*.*

acstest.audiocodes.be

(example)

MSFT-

Contact

Allow

IPG-ACS

Teams_52_121

(arbitrary name)

SI-ACS

52.121.*.*

acstest.audiocodes.be

(example)

MSFT-

Contact

Allow

IPG-ACS

Teams_52_122

(arbitrary name)

SI-ACS

52.122.*.*

acstest.audiocodes.be

(example)

MSFT-

Contact

Allow

IPG-ACS

Teams_52_123

(arbitrary name)

SI-ACS

52.123.*.*

acstest.audiocodes.be

(example)

MSFT-

Contact

Allow

IPG-ACS

3. Click Apply.

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5.14 Configure IP-to-IP Call Routing Rules

This section describes how to configure IP-to-IP call routing rules. These rules define the routes for

forwarding 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, and so 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

to ACS and vice versa. See AudioCodes' SBC documentation for more information on how to route in

other scenarios.

The following IP-to-IP Routing Rules will be defined:

◼ Terminate SIP OPTIONS messages on the SBC

◼ 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 >

IP-to-IP Routing).

2. Configure routing rules as shown in the table below:

Table 13: IP-to-IP Call Routing Rules

Index

Name

Source

IP Group

Request

Type

Call

Triger

Reroute

IP Group

Dest

Type

Dest

IP Group

Internal Action

Terminate

Options

Any

OPTIONS

Internal

(Response='200')

ACS to SIP Trunk

(arbitrary name)

IPG-ACS

IP Group

IPG-

SIPTrunk

SIP Trunk to ACS

(arbitrary name)

IPG-

SIPTrunk

IP Group

IPG-ACS

The configured routing rules are shown in the figure below:

Figure 32: Configured IP-to-IP Routing Rules in IP-to-IP Routing Table

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

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5.15 Configure Number Manipulation Rules

This section describes how to configure IP-to-IP number manipulation rules. These rules manipulate

the SIP Request-URI user part (source or destination number). The manipulation rules use the

configured IP Groups (as configured in Section 5.9 on page 36) to denote the source and destination

of the call.

Adapt the manipulation table according to your environment dial plan.

For example, for this interoperability test topology, a manipulation is configured to convert E.164

phone numbers format, used by ACS to national telephone number format, used by the SIP Trunk.

To do this, the "+" (plus sign) will be removed from the destination and source numbers (if it exists)

for calls from the ACS IP Group to the Generic SIP Trunk IP Group.

To configure a number manipulation rule:

1. Open the Outbound Manipulations table (Setup menu > Signaling & Media tab > SBC folder >

Manipulation > Outbound Manipulations).

2. Configure the rules according to your setup.

The figure below shows an example of configured IP-to-IP outbound manipulation rules for calls

between ACS IP Group and Generic SIP Trunk IP Group:

Figure 33: Example of Configured IP-to-IP Outbound Manipulation Rules

Rule Index

Description

Calls from ACS IP Group to SIP Trunk IP Group with the prefix source number "+", remove one digit

from left.

Calls from ACS IP Group to SIP Trunk IP Group with the prefix destination number "+", remove one

digit from left.

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5.16 Miscellaneous Configuration

This section describes miscellaneous SBC configurations.

5.16.1 Optimizing CPU Cores Usage for a Specific Service (relevant for Mediant

9000 and Software SBC only)

This section describes how to optimize the SBC's CPU cores usage for a specified profile to achieve

maximum capacity for that profile. The supported profiles include:

◼ SIP profile – improves SIP signaling performance, for example, SIP calls per second (CPS)

◼ SRTP profile – improves maximum number of SRTP sessions

◼ Transcoding profile – enables all DSP-required features, for example, transcoding and voice in-

band detectors

To optimize core allocation for a profile:

1. Open the SBC General Settings page (Setup menu > Signaling & Media tab > SBC folder > SBC

General Settings).

2. From the 'SBC Performance Profile' drop-down list, select the required profile:

3. Click Apply, and then reset the device with a burn-to-flash for your settings to take effect.

6. Verify the Pairing Between the SBC and ACS

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6 Verify the Pairing Between the SBC and ACS

After you have paired the SBC with ACS, validate that the SBC can successfully exchange OPTIONS

with ACS.

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 PS-ACS and verify that 'Status' is online. If you see a failure, you need to troubleshoot

the connection first.

Figure 34: Proxy Set Status

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

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A Syntax Requirements for SIP Messages 'INVITE'

and 'OPTIONS'

The syntax of SIP messages must conform with Microsoft 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

Strictly required. The deployment does not function correctly without the correct

configuration of these parameters.

A.2 Syntax Requirements for 'INVITE' Messages

Figure 35: 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.

A.3 Requirements for 'OPTIONS' Messages Syntax

Figure 36: Example of 'OPTIONS' message

◼ Contact header

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

AudioCodes SBC

- 47 -

• MUST: When sending OPTIONS 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, 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 this

document you can find the configuration instructions.

Table 14: Syntax Requirements for an 'OPTIONS' Message

Parameter

Where Configured

How to

Configure

Contact

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

> Local Host Name

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,

int-sbc1.audctrunk.aceducation.info. The name changes the host name in

the call received from the IP Group.

See Section 5.9.

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

AudioCodes SBC

- 48 -

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 the

specifics 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 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.

Table 15: Teams Direct Routing Interface - Technical Characteristics