Network Router User Manual

SmartSwitch Router User Reference Manual 45
Cell Scrambling
port <port list> Specifies the port, in the format: media.slot.port.vpi.vci
media Specifies the media type. This is at for ATM ports.
slot Specifies the slot number where the module is installed.
port Specifies the port number.
vpi Specifies the Virtual Path Identifier. This parameter identifies the virtual
path. This parameter is optional.
vci Specifies the Virtual Channel Identifier. This parameter identifies the
virtual channel. This parameter is optional.
An important concept when applying service class definitions is the concept of inheritance.
Since a service class definition can be applied to a virtual channel, virtual path, or an ATM
port, the actual connection can inherit the service class definition from any one of the
three. The virtual channel will inherit the service class definition that is directly applied on
it. If no service class was applied to the virtual channel, the connection will inherit the
service class applied to the virtual path. If no service class definition was applied to the
virtual path, then the connection will inherit the service class applied to the ATM port. If
no service class was applied to the port, then the default service class UBR is applied.
Cell Scrambling
Cell scrambling is useful for optimizing the transmission density of the data stream. Since
all transmissions use the same source clock for timing, scrambling the cell using a random
number generator converts the data stream to a more random sequence. This ensures
optimal transmission density of the data stream.
Enabling Cell Scrambling
This command allows you to enable cell scrambling for the PDH (plesiochronous digital
hierarchy) physical (PHY) interfaces available on the ATM line card, such as T1, T3, E1,
and E3 PHYs.
Note:
For cell scrambling on the SONET PHY interfaces, refer to the SONET commands.
To enable cell scrambling on an ATM port, enter the following command in Configure
mode:
Enables cell scrambling on an
ATM port.
atm set port <port list> pdh-cell-scramble on| off