In a survivable core server environment, the media gateway contains a priority list of survivable core servers. If for any reason, the communication between the media gateway and the main server is lost, the media gateway requests service from the highest ranking survivable core server on its list. The survivable core server accepts the request and assumes control of the media gateway.

The survivable core server provides the same functionality and the same capacity as the main server.

A single survivable core server can use the Processor Ethernet interface to connect to CDR, AESVCS, and CMS. Duplex servers can use the Processor Ethernet interface to connect to CDR and Avaya Aura® Messaging.

Communication Manager Release 6.0 and later has the following capabilities:

• Processor Ethernet (PE) is supported on simplex and duplex servers for the connection of H.323 devices, Gateways, SIP trunks, and most adjuncts.
• When Processor Ethernet is used on duplex servers, it must be assigned to an IP address, Active Server IP address, that is shared between the servers. This address is known in networking terminology as an IP-alias. The active server is the only server that will respond on the IP-alias.

The Communication Manager templates are available in following two categories:

1. Communication Manager survivable core server contains the following templates:

   • Duplex
   • Simplex
2. Communication Manager survivable remote server contains the following templates:

   • Simplex Survivable Remote
   • Embedded Survivable Remote

The following table provides information on template types that can be used as a survivable remote or core server for Communication Manager.

The survivable core server option provides survivability to an Avaya configuration by allowing survivable servers to be placed in various locations in the customers network.

In a survivable core environment, there is only one main server. The main server can be a single server, or a duplicated server. If the main server is a single server, all the survivable core servers in the configuration must also be a single server.

Through careful planning and consideration, the servers are placed in various locations in the network of the customer (see Survivable Core Server design and planning). Each survivable core server is administered on the main server. During administration, values are assigned to the survivable core server. After administration, system translations are synchronized between the main server and the survivable core server. Once the survivable core server receives the translations, it assigns its values to every media gateway in the configuration. This is true for all servers except those administered as a Local Only server. Local Only servers connect to media gateways in their same community. For more information on administering the values for survivable core server, see Survivable core server administration.

The media gateways in the configuration contain a list (called a priority list) of survivable core servers. The main server is always the highest ranking server on an media gateways’s priority list. The media gateway prioritizes the survivable core servers on its list using the administered values assigned by the survivable core server. The priority list is dynamic. Changes to the media gateways’s priority list may be caused by a change in the assigned value of a survivable core server, a server with a higher value bumping a server with a lower value off the list, or loss of communication with a survivable core server.