Carrier Access Axxius 800 ユーザーズマニュアル

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7-8
Axxius 800 - Release 2.2
DS3 Controller Card
Controller and DS3 Redundancy
Controller and DS3 Redundancy
Protection Modes
The Axxius 800 can be provisioned with one or two DS3 Controller cards and 
connections to one or two DS3 lines, which will provide the following levels of 
protection:
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Electronics Protection – when provisioned with two Controller cards and only 
one DS3 line, only the Controller cards can be protected
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Network Protection – when provisioned with one Controller and two 
independent DS3 lines, only the DS3 lines can be protected.
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Electronics and Network Protection – when provisioned with two Controller 
cards and two independent DS3 lines, both the controller cards and the DS3 lines 
can be protected
Electronics Protection Mode
In this mode there are two DS3 Controllers installed the Axxius 800, but only one DS3 
line connected. 
The electronics mode of protection provides Controller card redundancy. Because there 
is only one DS3 connected, there is no DS3 redundancy. The receive path from the DS3 
line is simultaneously applied to the receiver of both Controller cards (see Figure). This 
enables both controllers to monitor the condition of the DS3 line so both are 
continuously framed up to the incoming signal. The Controller-select signal disables 
the outputs of the low-speed receive paths on the standby Controller and enables the 
low-speed receive paths on the active controller. The active Controller’s transmit signal 
is connected to the transmit path of the DS3 line through a relay, while the standby is 
disconnected until a protection switch occurs.
The automatic redundancy mode is used to enable and disable protection switching. If 
the redundancy control process determines the active controller is malfunctioning, or a 
maintenance switch is invoked (the switch command), a protection switch will occur. 
This means that the active Controller relinquishes control to the secondary Controller. 
This is done by enabling the standby Controller’s receive path and disabling the 
originally active Controller’s low-speed receive path (Controller-select signal) and