Cisco Systems A9014CFD manual Example for GPS interface, 22-5

Chapter 22 Configuring Clocking

Configuring Network Clock for Cisco ASR 901 Router

	Command or Action	Purpose
Step 9	network-clock input-source priority	Configures a clock source line interface, an external timing
	{interface interface-name slot/port	input interface, GPS interface, or a packet-based timing
	top slot/port {external	recovered clock as the input clock for the system and
	slot/card/port [t1 {sf efs d4}
		defines its priority. Priority is a number between 1 and 250.
	e1 [crc4fascas [crc4] 2048k
	10m]}}	This command also configures the type of signal for an
		external timing input interface. These signals are:
	Example:	• T1 with Standard Frame format or Extended Standard
	Router(config)# network-clock	Frame format.
	input-source 1 interface top 0/12
		• E1 with or without CRC4
	Example for GPS interface	• 2 MHz signal
	Router(config)# network-clock	• Default for Europe or Option I is e1 crc4 if the signal
		type is not specified.
	input-source 1 external 0/0/0 10m
		• 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	Adds the clock recovered from the serial interfaces as one
	controller [t1/e1] slot/port	of the nominated sources, for network-clock selection.
	Example:
	Router(config)# network-clock
	input-source 10 controller e1 0/12
Step 11	network-clock revertive	Specifies whether or not the clock source is revertive.
		Clock sources with the same priority are always
	Example:	non-revertive. The default value is non-revertive.
	Router(config)# network-clock	In non-revertive switching, a switch to an alternate
	revertive	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	Allows transmitting the system clock to external timing
	priority {external slot/card/port	output interfaces.
	[t1 {sf efs d4} e1 [crc4fas	This command provides station clock output as per G.781.
	cas [crc4] 2048k 10m]}
		We recommend that you use the interface level command
	Example:	instead of global commands. Global command should
		preferably be used for interfaces that do not have an
	Router(config)#network-clock
		interface sub mode. For more information on configuring
	output-source system 55 external
		network clock in interface level mode, see Configuring
	0/0/0 t1 efs
		Network Clock in Interface Configuration Mode,
		page 22-6.

	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
OL-23826-09		22-5