CISCO-ATM-NETWORK-CLOCK-MIB
The MIB module for management of network clock distribution and the Network Clock Distribution Protocol (NCDP) in Cisco devices. In the context of this MIB 'network clock' refers to the clock signal that is used to time the physical interfaces. Network clock distribution refers to the distribution of a clock signal through a device and between devices for use by the physical interfaces. (See Bell Communications Research, GR-1244-CORE, 'Clocks for the Synchronized Network: Common Generic Criteria' and Bell Communications Research, GR-436-CORE, 'Digital Network Synchronization Plan'). NCDP is used to configure the network clocking hardware of the platform on which an NCDP entity exists. The underlying network clocking hardware in turn distributes a clock signal through the device for use by the physical interfaces. When all of the interfaces that support synchronous clock recovery in a network are timed to one master clock signal, the network is said to be synchronized. NCDP protocol entities residing on adjacent devices cooperate through the exchange of protocol messages to construct a spanning network clock distribution tree. The tree preserves the synchronous digital hierarchy. After NCDP has determined that its algorithm has converged it superimposes the clock distribution tree on the underlying network and the result is a synchronized network.