# PBX Cluster(v16.x)

{% hint style="info" %}
This topic is only applicable to the PortSIP PBX v16.1 and later versions.
{% endhint %}

This topic describes how to deploy the PortSIP PBX with cluster support for up to 1M+ users, \~50,000 online users(registered users/signed-in users), and \~10,000 simultaneous calls, support more meetings, and IVR, queue calls.

This article includes the following topics:

* [Topology](https://support.portsip.com/v16.x-maintenance-mode/pbx-cluster/topology)
* [Preparing Cluster Servers](https://support.portsip.com/v16.x-maintenance-mode/pbx-cluster/preparing-cluster-servers)
* [Configuring Cluster Servers](https://support.portsip.com/v16.x-maintenance-mode/pbx-cluster/configuring-cluster-servers)
* [Managing Cluster](https://support.portsip.com/v16.x-maintenance-mode/pbx-cluster/managing-cluster)
* [Configuring Cluster Servers for High Availability](https://support.portsip.com/v16.x-maintenance-mode/pbx-cluster/configuring-cluster-servers-for-portsip-pbx-ha)