ADC AVIDIA SWD4573I1, User Manual

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Chapter 21: Configuring Network Services
Avidia System Configuration and Management User Manual 425
7 In the Cell Scrambling box, Enable or Disable cell scrambling.
Enables or disables cell scrambling. Cell scrambling, used in Avidia, is not an ATM
defined format for DS1, but is implemented by many vendors. An ATM cell has two parts:
header and payload. Cell scrambling scrambles the payload so that it does not resemble the
header. In the event that an ATM network looses sync, it will attempt to synchronize on
what it sees as the cell header. In some cases, the cell payload can resemble the cell header,
so the network attempts to synchronize on the cell payload rather than the cell header.
Scrambling the cell payload precludes it from looking like a cell header. Choose to enable
or disable cell scrambling based on whether or not the ATM equipment in the network
supports cell scrambling.
8 In the ATM Mapping box, select one of the following options that is compatible with your
DS3 network:
• PLCP which provides the mapping of ATM cells to DS3 frames (12 ATM cells are
mapped to a DS3 frame) using the ATM Physical Layer Convergence Protocol (PLCP)
• Direct (default) which provides a direct mapping of ATM cells to DS3 frames, but does
not include the overhead of PLCP (such as frame alignment)
9 Do one of the following:
• To activate the new settings, click Set , then in the confirmation dialog click Back to
return to the DS3 Configuration window.
• To cancel the new settings, click Get . You can only cancel the settings if you have not
clicked Set .