SIP User's Manual  586  Document #: LTRT-12804 
  Mediant 800 MSBG 
 
8.5.1.2.2  Emergency State 
If the UAs detect that their primary (external) proxy does not respond, they immediately 
register to SAS and start routing calls to it.  
Figure  8-102: SAS Redundant Mode in Emergency State (Example) 
 
 
8.5.1.2.3  Exiting Emergency and Returning to Normal State 
Once the connection with the primary proxy is re-established, the following occurs: 
  UAs: switch back to operate with the primary proxy. 
  SAS: ignores REGISTER requests from the UAs, forcing the UAs to switch back to 
the primary proxy.  
Note: This is applicable only if the 'SAS Survivability Mode' parameter is set to 
'Always Emergency' (2). 
 
8.5.2  SAS Routing 
This section provides flowcharts describing the routing logic for SAS in normal and 
emergency states.