| Description | Network clock status and statistics for sources of network
clock. When the value of cncDistributionMethod is 'manual',
the managed system uses this table to select a source of
network clock for the managed system. Within this table a
physical entity that is a source of network clock is
identified by cncManualSourceId. Table entries are indexed
by priority (cncManualSourcePriority).
A source of network clock for the device may be an
oscillator local to the device, a Building Integrated
Timing Supply (BITS) port or an interface that supports
synchronous clock recovery. (BITS is explained in more
detail in Bell Communications Research, GR-436-CORE,
'Digital Network Synchronization Plan'.)
When the managed system initializes it creates a row for
the device's default source of network clock, (the entry
having cncManualSourcePriority with value 'default'). The
only operations allowed on the columnar objects in this
particular row are read operations.
Other rows are created or destroyed by a management station
or through the device's local management interface when a
source of network clock is configured or removed. When a
management station creates a row it creates it explicitly
using RowStatus with either createAndGo or createAndWait.
A row is not made active until a valid value for
cncManualSourceId is supplied. A management station may
perform a write operation on any columnar object while the
row is active or not in service.
The value of any instance of cncManualSourceId located in
the table is unique except when the value refers to the
device's default source of network clock; any instance of
cncManualSourceId within the table may have this value at
any time. |