TPO Clusters

The concept of TPO Clusters provides resilience to TPO servers.

Prior to delving into redundancy aspects, ensure that you are acquainted with the concepts of TPO Places and TPO Group ID

Multiple resilience modes are available depending on the needs and capabilities of the infrastructure.

Turrets systematically interact with TPOs using a name rather than an IP address.

This name follows a DNS naming convention, although DNS requests are employed selectively based on the chosen redundancy mode.

For more details on this 'DNS-like' naming convention, refer to the TPO and turret connection section.

HOT BACKUP: The redundancy is done within a group of TPOs, no turret decisions.

This is an N+M redundancy scheme where N nodes are active, and M nodes are in a passive state, prepared to take over in case of any failure in the active nodes. N+M <=7

This is a fast process (under 5 seconds) and preserves established calls providing seamless resilience to turrets.

A comparison of the 3 "hotbackup" modes is described here. At a glance,

•Virtual IP, based on an IP address that has to be move from one TPO to another in case of failure, rely on network arp redirection (gratuitous) and works with all PBX type.

•DNS, based on DNS requests giving additional flexibility but more complex to put in place and limited PBX support

•Session Persistency, gives additional flexibility compared to Virtual IP and DNS modes.