104 CHAPTER 4: CONFIGURING PATH BUILDER S330/S310 MODULES , PORTS , AND APPLICATIONSConfiguring theOC3/STM-1 PortTo configure the OC3/STM-1 port, follow these steps:The PathBuilder S310 does not support OC3/STM-1; the OC3/STM-1 port isdisabled on that device.1 From the Configuration Management menu, shown in Figure 50, select[1] Manage Card to display the List Card menu, shown in Figure 51.2 From the List Card menu, select [4] OC3 UNI to open the SONET UNIConfiguration menu, shown in Figure 74. This menu displays the currentconfiguration for the OC3/STM-1 port and provides options that allow you tochange certain settings.Figure 74 Configuring the OC3/STM-1 Port3 Set the following parameters as desired:Admin. Status—Administrative status: Out of Service or In Service.Sonet Interface Mode—The SONET interface supports two modes: OC3 andSTM-1. Choose the mode used at your location. OC3 is used most often in theUnited States, while STM-1 is common in other countries.ATM Payload Scramble—Enables (yes) or disables (no) payload scrambling forthe OC3/STM-1 port. The default is disabled (no). Payload scrambling is atechnique used to avoid certain transmission equipment behaviors (for example,erroneous alarm conditions) that are caused by sensitivity to certain bit patterns inthe ATM payload. When you set payload scrambling to yes, the ATM PayloadScramble scrambles the 48 byte payload in outgoing cells in a defined manner andunscrambles the payload in incoming cells. The payload scramble settings mustmatch at the two ends of the OC3/SDH trunk.Timing Source—The timing source for the OC3/STM-1 transmit clock.Loop—Configures the OC3/STM-1 port interface to use the input port Rx clockas the timing source; timing is received from the service “loop.” Select Loop ifthe OC3/STM-1 port is used for the network/carrier service termination, inwhich case the carrier (the service “loop”) typically provides the timing source.System—Configures the OC3/STM-1 port interface to use the internal systemclock as the timing source.
