Every RPD in a Cisco Remote PHY Shelf 7200 runs a Shelf Manager service on its local CPU. Each Shelf Manager provides services including software upgrade, configuration
download, and status monitor.
A Primary Shelf Manager is elected among all RPDs in an arbitration process that is facilitated
by the Fan Control Card (FCC) that is located in the Fan Tray. The Primary Shelf Manager
is responsible for all Shelf communication with external devices, as well as interaction
with Fan Control Card. The FCC keeps a coherent copy of each RPDs Shelf Manager state at
all times.
Keep alive messages are passed between RPD Shelf Managers through EOBC (Ethernet Out-Of-Band
Communications). If an RPD goes offline, the other RPDs will be made aware of this by
the absence of these periodic keep alive messages. If the RPD hosting the Primary Shelf
manager goes offline, a new Primary Shelf Manager will be elected among the remaining
Shelf Managers.
The Primary Shelf Manager election protocol essentially promotes the RPD with the lowest IP
address to Primary Shelf Manager status. This election process is dependent on EOBC via
the Fan Control Card.
When an RPD is inserted, the Shelf Manager on the newly installed RPD will detect the system
elected Primary Shelf Manager by monitoring keep alive messages from Primary Shelf
Manager. If there is no existing Primary Shelf Manager on chassis, this new inserted
Shelf RPD Shelf Manager will be the Primary Shelf Manager.
All RPDs monitor the presence of the Fan Control Card through a dedicated presence pin. If the Fan Control Card is removed,
all RPDs will be aware of this event. In this situation, IPC connections between Shelf Managers will fail and each RPD will
continue to operate independently. LCHA failover is not supported in this condition.
The following functions need to be met for the Shelf Manager:
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Keep alive: After IPC communication between shelf line cards and Fan
Control Card setup, there will be keep alive messages between shelf managers,
and keep alive between primary shelf manager and Fan Control Card manager. This
keep alive message is software process level message used to tracking IPC
connections between shelf line cards and Fan Control Card. It also used for
primary shelf manager role notification. If keep alive messages between primary
shelf manager to shelf managers are lost, primary shelf manager election
function will be executed and a new primary shelf line card manager will be
elected.
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Software upgrade: There are two methods for a software upgrade. One is
through CLI, another is through SSD. For CLI upgrading, only the Primary Shelf
Manager located on the Shelf Line Card CLI will accept software upgrade
operation. Upgrade operations on other Shelf Line Card CLI will be redirected to
the Primary Shelf Manager located shelf line card CLI. Primary shelf manager
will get the bundle image from CCAP or server side depend on configuration, then
dispatch the bundle image to Fan Control Card. The Fan Control Card will power
off the shelf line cards and reload self to achieve software upgrade
operation.
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Status collection: Primary Shelf Manager collects the status information
on all Shelf Line Cards, RPDs and Fan Control Cards.
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Reload shelf line cards: After the Primary Shelf Manager receives the
reload command from CLI, the Primary Shelf Manager will send IPC to all cards
including the Fan Control Card. The Fan Control Card will reload all cards after
30 seconds.
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Configuration download: The shelf chassis-related configuration is stored
on each shelf line card. The Primary Shelf Line Card will collect Shelf Line
Cards configuration and Fan Control Card related settings. Every time the Shelf
Line Card has a configuration change, it will trigger the Shelf Manager by
sending IPC to the Primary Shelf Manager to do the configuration sync, and the
configuration will send a copy to Fan Control Card through Primary Shelf
Manager.