9500 MXC User Manual
3DB 23063 ADAA - Rev 004 July 2007 Vol. V-1-15
DAC Protection
DAC/tributary protection (DAC redundancy) is provided by operating two
identical DACs as a protected pair.
The protectable DACs are:
• DAC 3xE3/DS3M
• DAC 1x155o
• DAC 2x155o
• DAC 2x155e
• DAC 155oM
Protection Logic
• The DACs are configured as primary and secondary. The primary is the default
online DAC for Tx and Rx.
• Tx and Rx tribs are independently switched meaning it is possible for one of the
DACs to be online Tx, and the other online Rx.
• When a switch occurs, all Tx and/or Rx tributaries are switched to the
protection partner.
• Switching is not hitless.
• Two protection options are provided, tributary protection, or always-on:
• Tributary Protection (TT):
“Y” cables connect the paired DACs to customer equipment.
In the Rx direction (from the customer) both DACs receive data, but
only the online Rx DAC sends this data to the TDM bus.
In the Tx direction, the online Tx DAC sends data to customer
equipment, the other mutes its Tx line interface.
• Tributary Always On (TA):
Separate cables connect each DAC to customer equipment.
In the Rx direction (from the customer) both DACs receive data, but
only the online Rx DAC sends this data to the TDM bus.
In the transmit direction both DACs send data to customer equipment,
and the customer equipment switches between these two “always on”
tributaries.
TA protection must be used where two 9500 MXC INU/INUes are to be
interfaced using protected DACs.
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