Nortel Networks 1000S Manuale Utente

 System architecture

The Call Server provides telephony services, such as call processing, and 
supports trunking features. It also acts as a database server for 
synchronization of configuration information with all MG 1000S systems.

A CS 1000S system can control a maximum of four MG 1000S systems and 
Expanders. 

A CS 1000S system with one Call Server supports up to 1000 IP Phones. You 
can network a CS 1000S system with other CS 1000S systems to support 
larger numbers of IP Phones.

The NTDK20 Small System Controller (SSC) card in the Call Server is the 
primary system processor. It controls the telephony services and call 
processing. Each MG 1000S is also equipped with an SSC card. 

The Call Server SSC controls the call-processing features of IP Phones and 
trunk interfaces when in normal mode of operation. 

The Call Server SSC synchronizes the configuration information on all 
MG 1000S SSC cards. The configuration data on all MG 1000S SSC cards 
always exactly matches the Call Server SSC configuration data. 

The card’s Security Device enables the activation of features assigned to the 
system, through the use of a series of keycodes.

The SSC card in the MG 1000S controls the MG 1000S interface and 
application cards, and acts as a survivable call processor. All MG 1000S SSC 
cards are synchronized with the call processing on the Call Server SSC card. 
This synchronization enables an MG 1000S SSC card to take over local call 
processing if the primary Call Server fails to respond. 

If the Call Server fails to respond, each MG 1000S SSC can become its own 
independent call processor. This means that in the event of Call Server failure, 
one MG 1000S SSC does not act as a Call Server for the rest of the system; 
they are all independent.