3Com 3C63100-AC-C - PathBuilder S600 Bridge/router Reference Manual page 124

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HAPTER ONFIGURING
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ATH UILDER ODULES
2 Configure the OC3/STM-1 card.
a Select [1] Card Information to display the OC3/STM-1 UNI Card Configuration
menu, shown in Figure 89. This menu displays the current configuration for the
OC3/STM-1 UNI module and provides options for changing certain parameters.
Figure 89 OC3/STM-1 UNI Card Configuration Menu
b Set the following parameters as desired:
Admin Status—Administrative Status: In Service or Out of Service.
Sonet Interface Mode—Synchronous Optical Network mode: OC3 or STM-1.
OC3 (SONET) is a high-speed synchronous system technology used on
fiber-optic cable networks. STM-1 (SDH or Synchronous Digital Hierarchy) is the
European equivalent of SONET.
ATM Payload Scramble—Enables (yes) or disables (No) payload scrambling
for the OC3/STM-1 port. Payload scrambling scrambles the 48-byte payload in
outgoing cells in a defined manner and unscrambles the payload in incoming
cells. It is a technique used to avoid certain transmission equipment behaviors
(for example, erroneous alarm conditions) that are caused by sensitivity to
certain bit patterns in the ATM payload. You must match this setting at the
two ends of the OC3/STM-1 trunk.
Peak Rate—The peak ATM payload, in Mbps: 1 to 155. This parameter is a
feature specifically designed for the PathBuilder S600. It allows you and your
service provider to traffic shape all connections to an optimum rate, assigned as
part of the ATM service contract.
Timing Source—The timing source for the OC3/STM-1 transmit clock: system
or loop. If you set the OC3/STM-1 Timing Source to system at one end of the
OC3/STM-1 trunk, you must set it to loop at the other end.
System—Configures the port interface to use the system reference clock
within the shelf as a reference for transmitting.
Loop—Configures the port interface to use the input port Rx clock as the
timing source; timing is received from the service "loop." Select this option
if the OC3/STM-1 UNI module is used for the network/carrier service
termination, in which case the carrier (the service "loop") typically provides
the timing source.
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