9A656-04 and 9A600 Configuration Guide1-5Overview1.3.5 Distributed ClockingThe 9A656-04 supports three clocking modes:Clock Recovery ModeThis clocking mode is required when the 9A656-04 is CONNECTED to the public ATMnetwork. In this mode, the 9A656-04 derives its transmit clock from the incoming line clock.Master Clock DistributionThis clocking mode is required when the 9A656-04 is PART of the public ATM network. Inthis mode, one 9A656-04 installed in the SmartSwitch 9500 chassis is configured as themaster clock for all other modules attached to the CTM backplane. The 9A656-04 that is themaster clock then distributes all clocking information to all the other modules.Local Clock ModeThis clocking mode may be used by the 9A656-04 if the master clock signal is lost, or in theabsence of any external clock source. In this mode each 9A656-04 installed in the chassis actsas its own clock source.1.3.6 ATM Adaptation Layer (AAL) SupportThe 9A656-04 supports all ATM Adaptation Layers, (AAL 1, AAL 3/4 and AAL 5).1.3.7 Management LAN Emulation ClientThe SmartSwitch 9500 system creates a default management LEC upon first initialization.The LEC automatically joins the default ELAN. Although all modules in the chassis arecapable of becoming the LEC, only one LEC is active in the system at one time. This isaccomplished through a LEC election algorithm.
