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22-5
Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
OL-23826-09
Chapter 22 Configuring Clocking
Configuring Network Clock for Cisco ASR 901 Router
Step 9
network-clock input-source
priority
{interface
interface-name
slot/port
| top
slot/port
| {external
slot/card/port
[
t1
{
sf
|
efs
|
d4
}
|
e1
[
crc4
|
fas
|
cas [crc4]
| 2048k
|
10m
]}}
Example:
Router(config)# network-clock
input-source 1 interface top 0/12
Example for GPS interface
Router(config)# network-clock
input-source 1 external 0/0/0 10m
Configures a clock source line interface, an external timing
input interface, GPS interface, or a packet-based timing
recovered clock as the input clock for the system and
defines its priority. Priority is a number between 1 and 250.
This command also configures the type of signal for an
external timing input interface. These signals are:
• T1 with Standard Frame format or Extended Standard
Frame format.
• E1 with or without CRC4
• 2 MHz signal
• Default for Europe or Option I is e1 crc4 if the signal
type is not specified.
• Default for North America or Option II is t1 esf if
signal type is not specified.
Note The no version of the command reverses the
command configuration, implying that the priority
has changed to undefined and the state machine is
informed.
Step 10
network-clock input-source
priority
controller [
t1/e1
]
slot/port
Example:
Router(config)# network-clock
input-source 10 controller e1 0/12
Adds the clock recovered from the serial interfaces as one
of the nominated sources, for network-clock selection.
Step 11
network-clock revertive
Example:
Router(config)# network-clock
revertive
Specifies whether or not the clock source is revertive.
Clock sources with the same priority are always
non-revertive. The default value is non-revertive.
In non-revertive switching, a switch to an alternate
reference is maintained even after the original reference
recovers from the failure that caused the switch. In
revertive switching, the clock switches back to the original
reference after that reference recovers from the failure,
independent of the condition of the alternate reference.
Step 12
network-clock output-source system
priority
{external
slot/card/port
[
t1
{
sf
|
efs
|
d4
}
|
e1
[
crc4
|
fas
|
cas
[
crc4
]
|
2048k
|
10m
]}
Example:
Router(config)#network-clock
output-source system 55 external
0/0/0 t1 efs
Allows transmitting the system clock to external timing
output interfaces.
This command provides station clock output as per G.781.
We recommend that you use the interface level command
instead of global commands. Global command should
preferably be used for interfaces that do not have an
interface sub mode. For more information on configuring
network clock in interface level mode, see Configuring
Network Clock in Interface Configuration Mode,
page 22-6.
Command or Action Purpose