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.
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.
Management Switch/Hub | Access | Access | Customer | |
Station | w/SNMP | Line Card | Line Card | Site |
|
| LLCF is ON | LLCF is ON |
|
| TX | FX |
| TX |
|
| Remote |
|
|
|
| Cable |
|
|
LED lit = established link | LED unlit = no link |
| ||
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.
Management Switch/Hub | Access | Access | Customer | |
Station | w/SNMP | Line Card | Line Card | Site |
|
| LLCF is ON | LLCF is ON |
|
| TX | Broken |
| TX |
|
| FX Remote |
| |
|
| Cable |
|
|
| Link Loss Carried Forward |
|
| |
LED lit = established link | LED unlit = no link |
| ||
Management Switch/Hub | Access | Access | Customer | |
Station | w/SNMP | Line Card | Line Card | Site |
TX
LLCF is ON
FX
Remote
Cable
LLCF is ON
Broken
TX
Cable
Link Loss Carried Forward
LED lit = established link | LED unlit = no link |
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.
* Cards are shipped with LLCF disabled (OFF).
Radiance Access Line Cards | 17 |