METRObility Optical Systems 2152-AA-01, 2152-AY-01, 2152-77-01 manual Copper Loss Carry Forward Clcf

Copper Loss Carry Forward (CLCF)

The copper-to-fiber “twister” incorporates CLCF for identifying a lost copper connection. When CLCF is enabled*, the fiber port’s transmitter shuts down if the copper port stops receiving link pulses. However, the copper port continually transmits link signals regardless of whether or not the fiber port detects link.

The diagram below shows a typical network configuration with good link status using two copper-to-fiber “twister” units for remote connectivity. Note that CLCF is enabled as indicated.

Management Switch/Hub							Switch/Hub Management
Station	w/SNMP	"twister"			"twister"		w/SNMP	Station
		CLCF is ON			CLCF is ON
	Copper			Fiber			Copper
	Cable	Port	Port	Cable	Port	Port	Cable
		1	2		2	1
LED lit = established link			LED unlit = no link

If a copper connection breaks, the “twister” will carry that link loss forward.

Management Switch/Hub				Switch/Hub Management
Station	w/SNMP	"twister"	"twister"	w/SNMP	Station
		CLCF is ON	CLCF is ON
	Broken
	Copper
	Cable
		Copper Loss Carried Forward
LED lit = established link		LED unlit = no link

Loss of link at the fiber port is not propagated, as shown in the example below.

Management Switch/Hub				Switch/Hub Management
Station	w/SNMP	"twister"	"twister"	w/SNMP	Station
			LLR2 is OFF
			Broken
			Fiber
			Cable
LED lit = established link		LED unlit = no link

*Units are shipped with CLCF disabled. CLCF is not applicable to fiber-to-fiber models.

14 User Guide