No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>

Reminder

To have a better experience, please upgrade your IE browser.

upgrade

The Incorrect Fiber Connection Causes That ASON Control Links at the Electrical Layer of the NG WDM Equipment Are Abnormal

Publication Date:  2012-07-25 Views:  53 Downloads:  0
Issue Description
On a WDM four-point ring, the equipment is the OptiX OSN 6800 R004 version, four OADM nodes in the anti-clockwise direction are NE20, NE21, NE22, and NE23. The networking mode is mesh networking. For details on the networking diagram, see the attachment. Each direction of the stations is configured with one NS2 board.
ASON services at the electrical layer are planned to be configured on the network. After the hardware is installed, the NODEID is configured according to the guide, the ASON feature is enabled, the ASON domain and the ASON NE are created, and the fiber connection is established on the T2000 side. The result of searching control links and TE links shows that TE links are normal, but only unidirectional control links are available between NE22 and NE21, and between NE22 and NE23. That is, control links are incomplete. 
 
Alarm Information
No alarm is generated on control links and TE links. The T2000 displays that certain service boards report LOS alarms. In consideration that control links are abnormal and no service is configured on the network, these alarms reported by service boards are not paid attention to. 
Handling Process
ASON control links are related to certain monitoring channels of the NG WDM equipment. Therefore, check the states of the monitoring channels of NE21, NE22, and NE23.
Check the SC1 or SC2 board at each station. The check result shows that no alarm is reported and the receive optical power is about �14 dBm, and it is normal. Open the NE Manager, and then check the DCC link state in the Communication interface. The check result shows that the receive and transmit states of the SC1 or SC2 board of all stations are normal. Maybe the direction of the established fiber connection between the OSC and the FIU is improper. The check result shows that the fiber connection on the T2000 side and the fiber connection on the equipment side are correct.
During control link generation, the LMP protocol works. Check the states of LMP links in the ASON Protocol Management > LMP Protocol Status interface. The check result shows that the states of the links related to the SC1 or SC2 board of all stations are UP, and this is normal.
According to the experience of configuring ASON services at the optical layer, the states of control links should be normal. After continuous uploading and synchronization operations, only the unidirectional control links are available between NE22 and NE21 and between NE22 and NE23.
The T2000 displays the LOS alarms that are reported by service boards. Through these alarms, locate the problems. The location result shows that the ODU-in interface in the transmit direction from NE22 to NE21 has the MUT_LOS alarm, the NS2-in interface in the receive direction from NE23 to NE22 has no receive optical signals, and other alarms are caused by the two alarms.
Clear the OBU alarm in the transmit direction from NE22 to NE21. The check result shows that the connected M40v-out interface does not transmit optical signals. Maybe the adjustable optical attenuator is not adjusted. As a result, the insertion loss of the M40v is over high. Adjust the attenuation value of the port corresponding to the M40v. The M40v still no output optical signals. Check the fiber connection on the equipment side. The check result shows that the channel port on the faulty M40v is connected improperly. The NS2 should be connected to the M35 interface. The check result shows that the NS2 is connected to the M40 interface. The NS2 frequency is 192.6 THz through confirmation. Therefore, the NS2 should be connected to the M35 interface actually. Adjust the optical power after adjusting the fiber. Then, the alarms related to the transmit direction from NE22 to NE21 are cleared.
Then, check ASON control links. Bidirectional control links between NE22 and NE21 are available. The problem is solved.
Next, handle the problem that the NS2 on NE23 does not have receive optical signals. Query the optical power of related links through the optical power query function of WDM trail management. The query result shows that the previous optical power of the NS2 is normal basically. Maybe this fault is also caused by the improper fiber connection. Check the fiber connection on the site. The check result shows that the fiber that should be connected to the D38 is connected to the D39. Connect the fiber properly. Then, the related alarms are cleared. Check ASON control links again. The check result shows that the links between NE22 and NE23 are normal. 
 
Root Cause
Control links are automatically detected and maintained by the Open Shortest Path First (OSPF) protocol. OSPF is transmitted by the D4�D12 bytes of the OSC. 
Suggestions
With regard to ASON services at the optical layer of the OptiX OSN 6800, control links are transmitted by using the D4�D12 bytes. No requirement is posed on service channels if only the related trails of the OSC are normal.
With regard to ASON services at the electrical layer of the OptiX OSN 6800, OSPF is transmitted by the overhead field of ODUk. Therefore, control links can be established after the optical channel is commissioned. 
 

END