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Path Switching
and Routing
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Basic voice path switching and call routing framework is
implemented by this layer. V5.2 and ISUP Call Processing use the services
provided by this module. This module also interfaces with the operator
interface software for definition of routing tables and path resources.
This software module resides on XEN (tone switching, time
switching) and CAS (space switching and call routing).
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V5.2 Call
Processing
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This software module handles complete V5.2 call processing
and interface management. It also interfaces with the System Maintenance module
for digital trunk fault handling. This module gets the subscriber database
information from the operator interface module.
This module resides mainly on the XEN card.
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ISUP Call
Processing
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This software module interacts with other switches to
establish the SS7 protocol. ISUP call state machine is implemented by this
layer.SS7 link and linkset definitions are obtained from the Operator
Interface module.
ISUP processing is carried out mostly on the XEN
processor.
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System
Maintenance
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System Maintenance software is responsible for maintaining
the health of the system. This module detects and recovers from hardware and
software failures. Hardware diagnostics are also run to pin-point the exact
fault. Operator Interface module provides a front end for all the maintenance
related actions.
System Maintenance software is controlled mainly from the
CAS card. XEN switchover logic and fault detection logic is implemented on
the XEN card. Digital trunk fault handling is also implemented on the XEN.
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Operator
Interface
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This software module maintains the configuration database
of the system. It manages operator commands, alarms and events. Almost all
software modules use the services of this module to interact with the
operator.
This functionality is controlled from the OMC. Database
and configuration change interfaces are implemented on the CAS and XEN cards.
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