Avaya 03-300430 User Manual

3. A particular Tone-Clock circuit pack can be made active by issuing the set tone-clock 

location [override] command. If the Tone-Clock to be made active is less healthy 

than the currently active one, no interchange will occur unless the override option is 

specified; without it a message will inform the user that it is required.

Once a Tone-Clock circuit pack is made active by the set tone-clock location 

command, it will stay active until either the set tone-clock location command is 

entered again to make the other circuit pack active, or until a fault occurs in the active 
Tone-Clock circuit pack, which causes the system to interchange Tone-Clocks.

Firmware-initiated Tone-Clock interchanges occur when the auto clock switching option is 
enabled, and the TN2312 IPSI circuit pack firmware detects a loss of clock or clock errors. After 
detecting a loss of clock/clock errors, and rather than waiting for system software to request a 
switch, the IPSI firmware will automatically switch the clock (when auto clock switching is 
enabled). The auto clock switching option is disabled during system restarts. 

Note:

The auto clock switching option is required by the IPSI circuit pack since the EAL 
connection to the PKT-INT (one of the IPSI circuit packs many functions) is over 
the server packet bus which must have a good clock for proper operation.

Note:

Stratum-3 clocking is not available for a port network supported by a TN2312 
(IPSI) circuit pack, or a port network where the Tone-Clock function is supplied by 
a TN2182.

This section discusses synchronization with a Stratum-3 or -4 clocking device.