In front-end/back-end topologies, front end plays the application role and back end plays the storage role. When you use a third-party storage server, you need the Avaya AxC/Directory server. You can combine up to three application servers to form a cluster and add a fourth server for redundancy. The cluster of application server communicates with the telephony server and a third-party storage server through the AxC/Directory server.
As the third-party server is the storage destination for user messages, the message store resides on a third-party, corporate storage server. The AxC/Directory server is used for notification capabilities, the LDAP database, and to provide communications between the application servers and the third-party storage server. The AxC/Directory server is also used to store user properties, name, and greeting recordings. All voice messages are stored on the user’s third-party storage server.
You can design your system with the location of the front-end application servers is remote from the back-end storage server. Due to this flexibility, you can choose either distributed or centralized system topologies for your organization.
Scalability and redundancy are the two reasons to choose a cluster configuration. You can group up to three application servers in a cluster, plus a fourth application server for redundancy. With 100 ports per server at 62 users per port, three servers support 18,600 users. The maximum number of active ports per cluster is 300.
