Microsoft Teams – Direct Routing – Part 2

Continuation from the previous blog discussing the configuration and setup of Sonus SBC as well as O365 tenant to support Microsoft Teams direct routing.

Certificate Requirement

All deployed SBC(s) must have a public certificate from a supported Public CA. When generating the CSR, the private key size should be at least 2048.
Note: domain for certificate is not supported.

Thomas Poett has a great article around certificates. His article can be found here:

Direct Routing Certificate Requirement

Wildcard certificate is also supported on Sonus SBC for Direct Routing.… [Keep reading] “Microsoft Teams – Direct Routing – Part 2”

Microsoft Teams – Direct Routing Deloyment – Part 1


The deployment configuration below has been done in Australia and will cover all the requirements and configuration to be able to get Direct Routing up and running without any issues.

Voice gateway used for Enterprise Voice – Sonus Session Border Controller (SBC) 2000.

Note: The same configuration holds good for Sonus SBC 1000.


If media bypass is required for the deployment, the gateway will require a public IP address. Also note that in order for media bypass to successfully work, the Teams users in the corporate network will need to route to the public interface of the SBC, as such firewall rules need to be amended to allow this.… [Keep reading] “Microsoft Teams – Direct Routing Deloyment – Part 1”

Skype for Business Standard Edition – Unable to failback once DR is invoked

During the process of “Invoke-CsPoolFailover” the process changes the “PoolState” of the primary server from Active to FailedOver state, if this is not addressed after the restoration of the primary server the failback will not work.

Figure 1: Primary Server FailedOver State

In order to failback the pool back to the primary server the “PoolState” will need to be set back to Active. This can be done by running the following command:

PS C:\Set-CsRegistrarConfiguration -Identity “”[Keep reading] “Skype for Business Standard Edition – Unable to failback once DR is invoked”

DR Failover for Skype for Business Standard Edition

The article takes you through step by step of carrying out both health check and invoking disaster recovery (DR) a standard edition environment. The diagram below shows the layout of the environment where the DR was carried out on:

Figure 1 – Environment Overview

Before proceeding to test DR you need to make sure the appropriate registrar information is available/configured in the environment otherwise you will get the following error during Pool Failover process:

Please check that the pool <Prod_S4B> is healthy as conditions such as high CPU, low available memory
 or any disabled services can delay (or in some cases result in unsuccessful) fail over operations.… [Keep reading] “DR Failover for Skype for Business Standard Edition”

Transferring Individual Transformation Table between two Sonus Gateways

Quick Hack for Transferring Sonus Transformation Table between two Sonus gateways

Recently I been working on migration of users from an aging Cisco platform to Skype for Business 2015 on premise platform.

Customer has two Sonus 2000 Voice Gateways connected to Enterprise grade SIP trunks providing an Active-Active connection for inbound calls.

Both gateways are connected to CUCM via SIP using 5060 as below:

Note: To meet Disaster Recovery requirements for the Business they had their Datacentre 50km+ from each other.… [Keep reading] “Transferring Individual Transformation Table between two Sonus Gateways”