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CHAPTER
22-1
Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
OL-23826-09
22
Configuring Clocking
This chapter provides information about configuring clocking on the Cisco ASR 901 Series Aggregation
Services Router.
Contents
• Restrictions, page 22-1
• Configuring Network Clock for Cisco ASR 901 Router, page 22-2
• Configuring PTP for the Cisco ASR 901 Router, page 22-18
Restrictions
• External interfaces like Building Integrated Timing Supply (BITS) and 1 Pulse Per Second (1PPS)
have only one port. These interfaces can be used as either an input interface or output interface at a
given time.
• The line to external option is not supported for external Synchronization Supply Unit (SSU).
• Time-of-Day (ToD) is not integrated to the router system time. ToD input or output reflects only the
PTP time, not the router system time.
• Revertive and non-revertive modes work correctly only with two clock sources.
• BITS cable length option is supported via platform timing bits line-build-out command.
• There is no automatic recovery from out-of-resource (OOR) alarms. OOR alarms must be manually
cleared using clear platform timing oor-alarms command.
• If copper Gigabit Ethernet port is selected as the input clock source, the link must be configured as
a IEEE 802.3 link-slave, using synce state slave command.
• BITS reports loss of signal (LOS) only for Alarm Indication Signal (AIS), LOS, and loss of frame
(LOF) alarms.
• The clock source line command does not support loop timing in T1/E1 controllers. However, the
clock can be recovered from T1/E1 lines and used to synchronize the system clock using the
network-clock input-source priority controller E1/T1 0/x command.
• Adaptive clocking is not supported in Cisco ASR 901 router.