User guide

3-17
Configuration Guide for Cisco DSLAMs with NI-2
OL-2074-03
Chapter 3 Initially Configuring the Cisco DSLAM
Configuring Network Clocking
Examples
This example sets up the DSLAM building-integrated time source (BITS) interface as the
highest-priority clock source, then configures the BITS interface for T1 at 0.6 dB (0 to 133 feet, or 0
to 40.5 meters).
DSLAM# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
DSLAM(config)# network-clock-select 1 BITS
DSLAM(config)# network-clock-select BITS T1 0.6db
This example configures ATM 0/1, the trunk, as the second-highest priority timing source.
DSLAM# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
DSLAM(config)# network-clock-select 2 atm 0/1
This example configures the DSLAM system clock as the third-highest priority timing source.
DSLAM# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
DSLAM(config)# network-clock-select 3 system
This example shows how to configure the network clock to revert back to the highest priority clock
source after a failure:
DSLAM(config)# network-clock-select revertive
DSLAM(config)#
Configuring the Transmit Clocking Source
To configure the location from which an interface receives its transmit clocking, perform the following
steps, beginning in global configuration mode:
Note When an interface has its clock source set to Network-Derived, the interface uses the highest-priority
valid clock source available (assuming that the network clock source is configured to be revertive).
Examples
This example configures ATM 0/1 to receive its transmit clocking from a network-derived source:
DSLAM(config)# interface atm 0/1
DSLAM(config-if)# clock source network-derived
DSLAM(config-if)#
This example displays the network clocking configuration shown in Figure 3-4:
DSLAM# show network-clocks
PLL failed: 58886; PLL Passed: 1082982
FAIL: 0; NCO: F984; REF: F982; ERR: 2; ERR_D: 0; MAG: -1;
clock configuration is NON-Revertive
Priority 1 clock source: BITS clock
Command Task
Step 1
DSLAM(config)# interface atm slot/port
Select the interface to be configured.
Step 2
DSLAM(config-if)# clock source {loop-timed | network-derived}
Configure the interface network
clock source.