soft-upgrade vs failover and back to/from 2nd-ary system

[Vance Shipley]

Reto,

I worked on Nortel Meridian 1 PBXs years ago.  As I recall the way
they handled a core processor crash was to audit the time switch
when it returned to service and build state for the connected calls.

	-Vance

On Tue, Jan 25, 2005 at 10:19:30PM -0800, Reto Kramer wrote:
}  
}  Matthias, can you give me an additional clarification w.r.t. to the 
}  telco domain. (A2) implies that if the system that owns the state 
}  crashes, the state is gone. I assume the telco applications you're 
}  referring to use a definition of availability that does not count such 
}  crashes as dropped calls?  I.e. are there telco applications in which 
}  one can loose the call signaling state and as long as the voice trunk 
}  remains up the call continues and is not counted as a drop?  I.e. as 
}  long as one is able to setup new calls (on a fresh backup system that 
}  needed none of the lost state transfered at all) life is good (modulo 
}  the lost opportunity to charge for a call)?