In front-end/back-end topologies, front end plays the application role and back end plays the storage role. Dedicated application servers communicate with the telephony server and a third-party storage server through the AxC/Directory 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 such that 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.
Although the capacity that the basic front-end/back-end single site configuration that supports 6,200 users is slightly more than the single server configuration, the advantage of the front-end/back-end single site configuration is scalability. If your organization grows, you can increase the capacity by installing a second application server, a third application server, and an additional server for redundancy.
