Configuring the Control Module and System Timing
Configuring system clocking
Stinger® MS+ Getting Started Guide
5-17
admin> write
SYSTEM written
Configuring trunk ports as eligible clock sources
The DS3-ATM, OC3-ATM, and E3-ATM profiles support Clock-Source and
Clock-Priority parameters for specifying whether the port can be used to source the
ATM network clock and feed it to the primary control module as the master clock for
the unit. Each of the two trunk ports can be configured as eligible or ineligible for this
use, and can be assigned a high, middle, or low priority for being elected as the clock
source. Following are the relevant parameters, shown with default settings:
[in DS3-ATM/{ any-shelf any-slot 0 }:line-config]
clock-source = not-eligible
clock-priority = middle-priority
[in OC3-ATM/{ any-shelf any-slot 0 }:line-config]
clock-source = not-eligible
clock-priority = middle-priority
[in E3-ATM/{ any-shelf any-slot 0 }:line-config]
clock-source = not-eligible
clock-priority = middle-priority
If more than one line is eligible to be the clock source, the system chooses the one
with the highest priority, as specified by the Clock-Priority setting. If multiple sources
of equal priority are present, the system selects the first valid clock source. (A clock
source is valid if the Clock-Source parameter is set to
eligible
and the DS3, OC3,
or E3 interface is synchronized.)
Once it has selected a clock source, the system uses that source until the source
becomes unavailable or a higher-priority source becomes available. If no eligible
external sources exist, the system uses an internal clock generated by the primary
control module.
Typical trunk port clock source configurations
The following sample commands configure both ports of a DS3-ATM module as
eligible clock sources, with the first port assigned a higher priority for this use:
admin> read ds3-atm { 1 trunk-module-1 1 }
DS3-ATM/{ shelf-1 trunk-module-1 1 } read
admin> set line-config clock-source = eligible
admin> set line-config clock-priority = high
admin> write
DS3-ATM/{ shelf-1 trunk-module-1 1 } written
Parameter
Setting
Clock-Source
Enable/disable obtaining the system clock signal from the
port. By default, ports are not eligible clock sources.
Clock-Priority
Priority of the interface as the system’s clock source (high,
middle, or low priority). Once the Stinger unit chooses a
clock source, it uses that source until the interface becomes
unavailable or a higher-priority source becomes available.
