Configuring Card System Clocking
56
FS6300 NMS User Manual
3 • Configuring Alarms and Clocking
Main Reference and Fallback Reference
The Main Reference and Fallback Reference parameters define a primary and secondary (fallback) reference for
the card system clock source (and for all blades in the chassis when the card’s clocking mode is defined as mas-
ter). The card will use the fallback reference if and only if the main reference becomes unavailable.
When defining the main and fallback clocking sources, you can select a WAN port or the card’s internal clock
pulse oscillator. The card will use the main reference as its system clocking source unless the main reference
fails or is disconnected.
When the main reference becomes unavailable, the card will switch to the fallback reference as its system clock-
ing source. Both parameters will be defined from the same set of possible values. For the fallback reference to
serve its purpose, however, you must define it by selecting a value different from the main reference. You must
also enable the card’s fallback mechanism (see below). For the card’s main and secondary clocking references,
you can choose:
– •
wan(602)
—Clocking derived from the network clock received at the WAN interface.
– •
internal(200)
—Uses the card’s internal free-running oscillator for the clock source.
Clock Fallback
Select to enable or disable the card’s fallback feature. The fallback feature, when enabled, allows the card to
switch to a secondary clock as follows:
–
Enable - Master or secondary mode
—The card, upon failure of the primary reference clock source, will
switch to the selected fallback reference clock source.
–
Disable - Slave Mode
—The card defaults (fallback feature options are not accessible to user) to system
for both main reference and fallback reference—since the slave cards do not provide clock to the chassis,
they receive clock from the system clocking bus provided by a master or secondary card.
Clock Auto Recover
Select to enable or disable the clock auto recover feature. The Auto Recovery Feature , when enabled, will cause
a card (in master or secondary mode), which is operating on fallback reference clock due to a failure of the pri-
mary reference clock, to switch back to primary reference clock when it becomes available.
When disabled, the card, operating on fallback reference clock, will not switch back to primary reference clock,
even if the primary reference becomes available.
Click
Submit
to commit your changes. You will need to record the current configuration to save your changes
to the card’s volatile memory. (See
“Record the current configuration”
on page 60).
