Configuring the Training Function on a 100GE Interface
Context
With the increase of transmission rate or frequency, attenuation of signal's high-frequency components becomes increasingly severe. To guarantee transmission performance of signals, it is necessary to compensate for signals, and commonly used compensation technologies are pre-emphasis and balancing. The pre-emphasis technology increases high-frequency components of signals at the transmit end of transmission lines to compensate attenuation during the transmission. However, the pre-emphasis technology increases crosstalk while amplifying high-frequency components. To solve this problem, the balancing technology is developed. The balancing technology is used at the receive end of transmission lines to function like a filter for filtering high-frequency crosstalk.
After the training function is enabled on a 100GE interface, the transmit end exchanges frames with the receive end to automatically set the pre-emphasis and balancing parameters, improving processing efficiency of the two technologies. Note that the negotiated parameters for the training function are obtained based on the site environment. If the site environment changes, for example, from high-temperature environment to low-temperature environment, the parameters may be inaccurate. Therefore, bit errors may occur when the training function is enabled. The training function is optional in IEEE802.3 standards, and its implementation on different types of products from various vendors may differ.
When connecting two devices, enable or disable the training function on both ends simultaneously. By default, the training function is enabled on a 100GE interface. If the training function is disabled on the remote device or the remote device does not support the function, run the training disable or undo training enable command to disable the function.
Only the ES1D2C04HX2E and ES1D2H02QX2E cards of the X2E series, ES1D2C04HX2S and ES1D2H02QX2S cards of the X2S series support this command.
The training disable and undo training enable commands can be configured on a 100GE interface only when the interface connects to a 40GE cable.
Procedure
- Run system-view
The system view is displayed.
- Run interface interface-type interface-number
The interface view is displayed.
- Run training disable or undo training enable
The training function is disabled on the interface.
By default, the training function is enabled on an interface.
Precautions
After a 40GE cable is installed on a 100GE interface without the training disable configuration, the training enable configuration is automatically generated on the interface.
If no cable is installed on an interface, only the training enable and undo training disable commands can be configured on the interface.
- If the display this include-default command is run on an interface to view the training configuration after a cable is installed on the interface, the default training enable configuration is always displayed in the command output and does not change with the training configuration change.
The training configuration on an interface takes effect only after a cable is installed on the interface. If the cable is replaced with an optical module, the training disable and training enable configurations will be automatically deleted from the interface.
