Contents

Configuring OTN·· 1

About OTN· 1

OTN benefits· 1

OTN frame structure· 1

OTN tasks at a glance· 1

Enabling OTN mode on an interface· 1

Setting the FEC mode· 2

Setting the FEC-TCA alarm triggering threshold and detection interval 2

Setting the FEC-TCA alarm recovering threshold and detection interval 3

Setting the TTI 3

Setting the OTU-SD alarm threshold· 4

Enabling alarms and setting the alarm action· 4

Display and maintenance commands for OTN· 4

 

Configuring OTN

About OTN

An Optical Transport Network (OTN) is an optical network relying on the wavelength division multiplexing technology.

OTN benefits

An OTN features the following benefits:

·     Large scheduling granularity which meets transmission requirements of high-bandwidth services.

·     Reliable, dynamic, and flexible transmission through high-efficient node scheduling.

OTN frame structure

An OTN frame contains the following layers:

·     Optical Channel Payload Unit (OPU)—Maps customer signals into a frame structure, such as IP packets and Ethernet frames.

·     Optical Channel Data Unit (ODU)—Provides signal-independent connectivity to ensure the data channel connection of the OPU.

·     Optical Channel Transport Unit (OTU)—Provides Forward Error Correction (FEC) and optical layer protection and monitoring.

OTN tasks at a glance

To configure OTN, perform the following tasks:

1.     Enabling OTN mode on an interface

2.     (Optional.) Setting the FEC mode

3.     (Optional.) Setting the FEC-TCA alarm triggering threshold and detection interval

4.     (Optional.) Setting the FEC-TCA alarm recovering threshold and detection interval

5.     (Optional.) Setting the TTI

6.     (Optional.) Setting the OTU-SD alarm threshold

7.     (Optional.) Enabling alarms and setting the alarm action

Enabling OTN mode on an interface

About this task

During startup, the switch automatically creates a Dense Wavelength Division Multiplexing (DWDM) interface for each 100-GE interface that supports OTN. You can configure OTN settings on DWDM interfaces. The OTN settings take effect after you enable OTN mode on the corresponding Ethernet interfaces. For more information about Ethernet interface configuration, see Interface Configuration Guide.

Restrictions and guidelines

You must enable OTN mode on the Ethernet interfaces at the two ends of a link.

Procedure

1.     Enter system view.

system-view

2.     Enter 100-GE interface view.

interface hundredgige hundredgige-interface-number

3.     Enable OTN mode.

otn-mode enable

By default, an interface is operating in LAN mode.

4.     Return to system view.

quit

5.     Enter DWDM interface view.

controller dwdm dwdm-interface-number

The number of a DWDM interface is the same as the number of the corresponding 100-GE interface.

Setting the FEC mode

About this task

FEC improves the transmission reliability and signal transmission distance by using an algorithm to correct errors in data transmission.

Restrictions and guidelines

You must set the same FEC mode on the DWDM interfaces at the two ends of a link.

Procedure

1.     Enter system view.

system-view

2.     Enter DWDM interface view.

controller dwdm dwdm-interface-number

3.     Set the FEC mode.

fec { standard | enhanced | none }

By default, the FEC mode is set to standard.

Setting the FEC-TCA alarm triggering threshold and detection interval

About this task

This task enables the hardware to monitor the bit error rate. If the bit error rate for every second exceeds the FEC-TCA alarm triggering threshold within a detection interval, an FEC-TCA alarm is generated.

Procedure

1.     Enter system view.

system-view

2.     Enter DWDM interface view.

controller dwdm dwdm-interface-number

3.     Set the FEC-TCA alarm triggering threshold and detection interval.

fec-tca trigger { threshold trigger-coefficient trigger-power | interval trigger-time-interval }*

By default, the FEC-TCA alarm triggering threshold is e-6, and the detection interval is 3 seconds.

Setting the FEC-TCA alarm recovering threshold and detection interval

About this task

This task enables the hardware to monitor the bit error rate. If the bit error rate for every second is below the FEC-TCA alarm recovering threshold within a detection interval, an FEC-TCA alarm is cleared.

Procedure

1.     Enter system view.

system-view

2.     Enter DWDM interface view.

controller dwdm dwdm-interface-number

3.     Set the FEC-TCA alarm recovering threshold and detection interval.

fec-tca recover { threshold recover-coefficient recover-power | interval recover-time-interval }*

By default, the FEC-TCA alarm recovering threshold is e-7, and the detection interval is 30 seconds.

Setting the TTI

About this task

The Trail Trace Identifier (TTI) is an overhead in OTUs and ODUs. It is used for identifying an optical channel connection by the source access point when multiple optical channel connections exist.

Restrictions and guidelines

For a link, make sure the sent TTI of one end is the same as the expected TTI of the other end.

The TTI must contain a minimum of two forward slashes (/), for example, #&/123/abc.

Procedure

1.     Enter system view.

system-view

2.     Enter DWDM interface view.

controller dwdm dwdm-interface-number

3.     Set the TTI.

tti { odu-pm | otu } { expected | sent } ascii value

By default, the TTI is empty (0 in ASCII format).

Setting the OTU-SD alarm threshold

About this task

After you set the OTU-SD alarm threshold, if the bit error rate for every second exceeds the OTU-SD alarm threshold within a detection interval, an OTU-SD alarm is generated. This detection interval is not user-configurable.

Procedure

1.     Enter system view.

system-view

2.     Enter DWDM interface view.

controller dwdm dwdm-interface-number

3.     Set the OTU-SD alarm threshold.

sd otu threshold coefficient power

By default, the OTU-SD alarm threshold is e-6.

Enabling alarms and setting the alarm action

About this task

This feature enables the device to shut down a DWDM interface when an enabled alarm is triggered on the interface.

Procedure

1.     Enter system view.

system-view

2.     Enter DWDM interface view.

controller dwdm dwdm-interface-number

3.     Enable alarms and set the alarm action.

¡     Enable specified alarms and set the alarm action to link down.

alarm-detect { fec-tca | odu-ais | odu-lck | odu-oci | opu-plm | otu-biae | otu-sd | otu-lom | otu-oom | pm-bdi | pm-tim | r-lof | r-los | r-oof | sm-bdi | sm-iae | sm-tim } * action link-down

¡     Enable all alarms and set the alarm action to link down.

alarm-detect all

By default, all alarms are disabled on a DWDM interface.

Display and maintenance commands for OTN

Execute display commands in any view and reset commands in user view.

 

Task	Command
Display DWDM interface information.	display controller [ dwdm [ interface-number ] ]
Clear bit error statistics on DWDM interfaces.	reset counters controller dwdm [ interface-number ]