Link Loss Carry Forward (Llcf) - LANCAST twister 2111-12-01 Installation & User Manual

Link Loss Carry Forward (LLCF)

*
The "twister" 2111has been designed with a LLCF function for trouble-
shooting a remote connection. The unit is shipped with the LLCF disabled.
When LLCF is enabled, the fiber optic ports as well as the twisted-pair ports
on the 2111 do not transmit a link signal until they receive a link signal from
the opposite port. For example, if LLCF is enabled and two "twister" media
converters are connected via a fiber cable with nothing else connected to them,
the Link LED does not illuminate. When a valid link is established at the
twisted-pair port, a complete connection is accomplished.
The diagram below shows a typical network configuration using a "twister"
media converter for remote connectivity:
Management Switch/Hub Switch/Hub Management
"twister" "twister"
Station w/SNMP w/SNMP Station
Remote
up to 15km
LED lit = established link LED unlit = no link
If the fiber connection breaks, or the remote device fails, the "twister"
media converter carries that link loss all the way to the switch/hub which
generates a trap to the management station. The administrator can then
look at the media converter to determine the source of the loss.
Management Switch/Hub Switch/Hub Management
Station w/SNMP "twister" "twister" w/SNMP Station
Broken
Remote
Trap generated Cable Trap generated
Link Loss Carried
LED lit = established link LED unlit = no link
IMPORTANT: When connecting a "twister" media converter with LLCF
enabled to an auto-negotiating device, force both sides of the configura-
tion to either 10 or 100Mbps full or half duplex. This allows the media
converter to immediately see link pulses and start passing data.
* Does not apply to the "twister" 2111-12 (BNC).
"twister" 2111 Media Converter 17