METRObility Optical Systems R231-17 User Manual
Radiance Access Line Cards 17
Link Loss Carry Forward (LLCF)
*
The access line cards incorporate an LLCF function
for troubleshooting a remote
connection. When LLCF is enabled, the ports do not transmit a link signal until
they receive a link signal from the opposite port.
they receive a link signal from the opposite port.
The diagram below shows a typical network configuration with a good link
status using access line cards for remote connectivity. Note that LLCF is enabled
as indicated in the diagram.
status using access line cards for remote connectivity. Note that LLCF is enabled
as indicated in the diagram.
Management
Station
Switch/Hub
w/SNMP
Customer
Site
Access
Line Card
Access
Line Card
LED lit = established link
LED unlit = no link
LLCF is ON
LLCF is ON
TX
TX
FX
Remote
Cable
If the fiber connection breaks, the card carries that link loss forward to the
switch/hub which generates a trap to the management station. The administrator
can then determine the source of the problem.
switch/hub which generates a trap to the management station. The administrator
can then determine the source of the problem.
Link Loss Carried Forward
LED lit = established link
LED unlit = no link
Management
Station
Switch/Hub
w/SNMP
Customer
Site
Access
Line Card
Access
Line Card
LLCF is ON
LLCF is ON
TX
TX
Broken
FX Remote
Cable
Link Loss Carried Forward
LED lit = established link
LED unlit = no link
Management
Station
Switch/Hub
w/SNMP
Customer
Site
Access
Line Card
Access
Line Card
LLCF is ON
LLCF is ON
TX
Broken
TX
Cable
FX
Remote
Cable
Important: When connecting a line card with LLCF enabled to an auto-
negotiating device, force both sides of the configuration to 100Mbps and either
full or half duplex. This allows the card to immediately see link pulses and start
passing data.
negotiating device, force both sides of the configuration to 100Mbps and either
full or half duplex. This allows the card to immediately see link pulses and start
passing data.
* Cards are shipped with LLCF disabled (OFF).