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Configuration • 1:1 Chassis Redundancy Overview
APEX1000 All-Purpose Edge QAM Software Version 2.4.x • Installation and Operation Manual
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573408-001-a
Primary and Secondary APEX Roles
•
The primary APEX is the
master
device in the redundancy pair, and is typically
expected to source broadcast content to the cable plant. This is the device which is
normally
on
and
active
(assuming that no faults have occurred).
•
The secondary APEX is the
backup
device in the redundancy pair; it has its QAM
Module outputs muted, and is
standing by
. The secondary device only acts when the
primary APEXs heartbeat indicates a failover should occur, or when communication
with the primary times out.
Failover Procedure
1.
Each APEX sends a heartbeat at one second intervals. As soon as the primary and
secondary exchange heartbeats, the redundancy link is established. The heartbeat
informs each APEX of the status of the other APEX in the redundancy pair, and
includes configuration synchronization information.
2.
Each APEX then verifies if the configurations are synchronized. If they are not, the
standby APEX retrieves configuration information from the active APEX.
3.
When the primary APEX experiences a fault, it transitions from the active state to
the fault state, muting its QAM outputs. If possible, the primary sends a heartbeat to
signal this transition.
4.
The secondary APEX (previously in a standby state) then transitions to the active
state, un-muting its broadcast QAM outputs upon reception of the heartbeat from
the primary APEX, or times out while waiting for the heartbeat from the primary.
You can view the status of both primary and secondary APEX on each APEX-EM. When
the primary is in a standby state, you can force a failback from the secondary back to the
primary.
CAUTION
There is no auto-switchback option; you must manually failback to the primary after the
primary comes back online. However, if the secondary experiences a fault, the primary
becomes active.
The APEX will enter a fault state on the following critical alarms:
•
QAM Channel Fault
Note: HW Fault is enabled by default; you can enable or disable the other alarms.
Additionally, you can also determine if the link loss of the following interfaces will result
in the APEX entering a fault state:
