This MIB module is intended for the management of network clock distribution and the Network Clock Distribution Protocol (NCDP) in Cisco MGX ATM switches. This MIB allows enabling automatic network clock configuration and distribution as well as configuration of manual clock sources. NCDP allows automatic distribution of network clocking sources in the network. A spanning network clock distribution tree is constructed by each node in the network and each node is synchonized to one single 'master' clock reference. A source of network clock for the device may be an oscillator local to the device or a Building Integrated Timing Supply (BITS) port or an interface that supports synchronous clock recovery. An 'index'('cwnClockSourceIndex') is assigned by the NCDP protocol entity in the managed system to identify each available source of network clock on the managed system.