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.