Detailed Ess Overview; No Service Timer - Avaya ESS User Manual

ESS Overview

Detailed ESS Overview

In an ESS environment, there is one Main server. The Main server can be a simplex server
(S8500 Media Server), or a duplex server (S8700 series media server). If the Main server is an
S8500 Media Server, all ESS servers in the configuration must also be S8500 Media Servers.
Through careful planning and consideration, S8700 and/or S8500 Media Servers are placed in
various locations in the customer's network (see
page 63). Each ESS server is administered on the Main server. During administration, values
are assigned to the ESS server. After administration, system translations are synchronized
between the Main server and the ESS server. Once the ESS server receives the translations, it
advertises its values to every IPSI in the configuration, unless it was administered with as a
Local Only server. Local Only servers only advertise to IPSIs in their same community. For more
information on administering the values for ESS see
The IPSIs in the configuration contain a list (called a priority list) of ESS servers. The Main
server is always the highest ranking server on an IPSI's priority list. The IPSI prioritizes the ESS
servers on its list using the administered values advertised by the ESS server. The priority list is
dynamic. Changes to the IPSI's priority list may be caused by changes in an ESS server's
advertised value(s), or loss of communication with an ESS server.

No service timer

During ESS administration, a value is entered for the no service timer. The value of the no
service timer determines the amount of time the IPSI waits to request service from an ESS
server, after losing communication with the Main server, or the controlling ESS server. The
interval from when the no service timer actives, to the time the IPSI requests service of an ESS
server, is called the no service time out interval. The value for the no service timer is
administrable from three to 15 minutes, with a default of five minutes. For more information on
the no service timer see,
18 Avaya Enterprise Survivable Servers (ESS) Users Guide
System-parameters ess form - page seven
Chapter 2: ESS Design and Planning
Administering ESS
on page 126.
on
on page 122.