Handling Impassable Control Channels

Control channels are classified into control channels inside and outside fibers. The control channels inside fibers use D4-D12 bytes to transmit the check information. The control channels outside fibers are seldom used.

Common Causes for Impassable Control Channels

Common causes for impassable optical-layer control channels are listed as follows:

The physical fiber between the OSC and FIU is improperly connected.
The fiber connection between the FIU and OSC is wrongly configured on the Web LCT.
The SD/SF alarm exists at the OSC port.
The number of the OSC ports exceeds the limit. (An OSC port should be uniquely mapped to a control channel. A maximum of 40 control channels are allowed to fail in the verification.)
The opposite NE is not an ASON NE or the ASON feature is not successfully enabled.
The LMP Protocol Status is manually set to Disabled.
The point-to-point protocol (PPP) fails because of the bit errors in the CPU channel.

Common causes for impassable electrical-layer control channels are listed as follows:

The SD/SF alarm exists at the corresponding port of the TTI.
The corresponding server trail for the TTI is not created or is already deleted.
The number of the OSC and TTI ports exceeds 40. (An OSC port should be uniquely mapped with a control channel.)
The opposite NE is not an ASON NE or the ASON feature of the opposite NE is not successfully enabled.
The LMP Protocol Status is manually set to Disabled.
The point-to-point protocol (PPP) fails because of the bit errors in the CPU channel.

Procedure

Optical-layer control channel
1. Check the fiber connection according to the networking.
2. Check whether the bidirectional fiber connection between an FIU and the corresponding OSC is correctly configured.
3. Check whether alarms exist at the OSC port. If alarms exist, clear the alarms.
4. If control channels are excessive, disable certain control channels.
5. Check the running status of the ASON feature of the opposite NE. If the running is abnormal, confirm whether the ASON feature needs to be run. If yes, enable the ASON feature.
6. Check whether the status of the LMP protocol at the FIU port is set to Disabled. If yes, modify the status to Enabled.
7. Check the error bit performance events on the fibers and optical interface for the OSC. Check whether a large number of error bits exist and cause the impassability of the control channel.
Electrical-layer control channel
1. Check whether alarms exist at the corresponding port of the TTI. If alarms exist, clear the alarms.
2. Create a corresponding server trail from the TTI.
3. If control channels are excessive, disable certain control channels.
4. Check the running status of the ASON feature of the opposite NE. If the running is abnormal, confirm whether the ASON feature needs to be run. If yes, enable the ASON feature.
5. Check whether the status of the LMP protocol at the FIU port or at the corresponding port of the OTN board is set to Disabled. If yes, modify the status to Enabled.
6. Check the error bit performance events on the fibers and optical interface for the OSC. Check whether a large number of error bits exist and cause the impassability of the control channel.