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 Master 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 Master 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 Master Shelf manager goes offline, a new Master Shelf Manager will be elected among the remaining Shelf Managers.
The Master Shelf Manager election protocol essentially promotes the RPD with the lowest IP address to Master 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 Master Shelf Manager
by monitoring keep alive messages from master Shelf Manager. If there is no existing Master Shelf Manager on chassis, this
new inserted Shelf RPD Shelf Manager will be the Master 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 master 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 master shelf
manager role notification. If keep alive messages between master shelf manager to shelf managers are lost, master shelf manager
election function will be executed and a new master 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 Master
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 Master Shelf Manager located shelf line card CLI. Master 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: Master 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 Master Shelf Manager receives the reload command from CLI, the Master 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 Master 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 Master Shelf Manager to do the configuration sync, and the configuration
will send a copy to Fan Control Card through Master Shelf Manager.