Carrier Access Network Device Axxius 800 - Manual (Page 380)

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:
l Electronics Protection – when provisioned with two Controller cards and only
one DS3 line, only the Controller cards can be protected
l Network Protection – when provisioned with one Controller and two
independent DS3 lines, only the DS3 lines can be protected.
l 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