Alcatel-Lucent 9500 MXC User Manual page 417

3DB 23063 ADAA - Rev 004 July 2007
• In the Tx direction, the online Tx DAC/IDU sends data to customer equipment,
the other 'mutes' its Tx line interface.
Tributary Always On (TA)
• Separate cables connect each DAC/IDU to customer equipment.
• In the Rx direction (from the customer) both DAC/IDUs receive data, but only
the online Rx DAC/IDU sends this data to the bus/radio.
• In the transmit direction both DAC/IDUs send data to customer equipment, and
the customer equipment switches between these two 'always on' tributaries.
• TA protection can also used where two 9500 MXC INU/INUes are
trib-interfaced using protected DACs, or where two pairs of protected IDUs are
trib interfaced, but doing so will reduce the level of protection on offer
compared to TT protection (Y cables).
• For example, in the event of a trib module failure both the failed and
connected DACs must switch to the standby DACs using TA protection,
whereas with TT protection only the failed DAC is switched.
Hot Standby: No Tributary Protection
• This only applies to the IDU 20x when configured for Hot Standby: No
Tributary Protection, which is required for capacities above 20xE1 / 16xDS1.
For more information, refer to Additional Procedures for IDU 300 20xV2 on
page 8-23.
In protected mode the DAC/IDUs are configured as primary and secondary. The
primary is the default DAC/IDU for online Rx and Tx.
• For a Node the protection DAC switching operates independently for Rx and
Tx, meaning it is possible for one of the DACs to be the online Tx, and the other
online Rx. The exception is DAC 155oM; when a switch event occurs both Rx
and Tx are simultaneously transferred to the standby DAC 155oM.
• For a Terminal the DAC Tx and Rx online functions follow the IDU Tx and Rx
online status. The primary-designated IDU is default online for Tx and Rx
• In the event of an IDU Tx switch, Rx online is also switched such that Tx
and Rx online are with the same IDU.
• In the event of an IDU Rx online switch, IDU Tx is not switched, meaning
one IDU is online Tx, and the other online Rx.
When a DAC/trib switching event occurs, all Tx and/or Rx tributaries are
switched to the protection partner.
9500 MXC User Manual
Vol. IV-7-27