Link Loss Carry Forward (LLCF)*
The Access Optical Network Unit incorporates Link Loss Carry Forward as an aid in 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.
Warning: If LLCF is enabled on the Access ONU and its copper port loses link, you will be unable to manage the ONU. Only enable LLCF when notification of a link loss is more important than remote management functionality.
The diagram below shows a typical network configuration with a good link status using a Radiance Access Line Card and an Access ONU for remote connectivity. Note that LLCF is enabled as indicated in the diagram.
Management Switch/Hub | Access | Access | Customer | |
Station | w/SNMP | Line Card | ONU | Site |
|
| LLCF is ON | LLCF is ON |
|
| TX | FX |
| TX |
|
| Remote |
|
|
|
| Cable |
|
|
LED lit = established link | LED unlit = no link |
| ||
If a connection breaks, as shown below, one or both line cards will carry 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 | ONU | 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 | ONU | 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 an Access ONU with LLCF enabled to an auto- negotiating device, force both sides of the configuration to the same duplex and speed. This allows the unit to immediately see link pulses and start passing data.
*The unit is shipped with LLCF disabled (OFF).
Radiance 10/100Mbps Access Optical Network Unit | 17 |