Cisco ASR 900 Series Configuration Guide

•
ACR is supported only for CEM circuits with MPLS PW encapsulation. ACR is not supported for CEM
circuits with UDP or IP PW encapsulation.
•
The clock recovered by an ACR clock for a CEM circuit is local to that CEM circuit. The recovered
clock cannot be introduced to another circuit and also cannot be introduced to the system clock as a
frequency input source.
•
The clock ID should be unique for the entire device.
•
When a CEM group is configured, dynamic change in clock source is not allowed.
•
Physical or soft IM OIR causes the APS switchover time to be higher (500 to 600 ms). Shut or no shut
of the port and removal of the active working or protect also cause the APS switchover time to be high.
To overcome these issues, force the APS switchover.
Prerequisites for ACR Configuration in 8 T1/E1 Interface Module
•
Ensure that CEM is configured before configuring the adaptive clock recovery.
•
The following must be configured before configuring the ACR:
•
The remote Customer Equipment and the remote Provider Edge device. These can be configured
by using the clock source internal and the clock source line commands under the T1/E1 controller.
•
The controller on the local Customer Equipment connected to the ACR router by using the clock
source linecommand.
•
PRC or PRS reference clock from a GPS reference to the remote Customer Equipment or remote
CEM Provider Edge device.
Configuring ACR for T1 Interfaces for SAToP
To configure the clock on T1/E1 interfaces for SAToP in controller mode:
enable
configure terminal
controller t1 0/4/3
clock source recovered 15
cem-group 20 unframed
exit
To configure the clock recovery on T1/E1 interfaces in global configuration mode:
recovered-clock 0 4
clock recovered 15 adaptive cem 3 20
exit
The clock source recovered configuration on the controller must be completed before configuring the
clock recovery in global configuration mode.
Note
On the controller, the clock source should be configured before CEM group is configured.Note
1-Port OC-192 or 8-Port Low Rate CEM Interface Module Configuration Guide, Cisco IOS XE Everest 16.7.x (Cisco
ASR 900 Series)
135
Clock Recovery System for SAToP
Benefits of ACR for 8 T1/E1 Interface Module

Cisco ASR 900 Series Specifications

General

Brand	Cisco
Model	ASR 900 Series
Category	Network Router
Language	English