Configuring Bit-Error-Triggered Trunk Update

To cope with bit errors detected on trunk member interfaces, configure bit-error-triggered trunk update.

Usage Scenario

If bit errors are generated or cleared on a trunk member interface, bit-error-triggered trunk update triggers the trunk interface to delete or re-add the member interface from or to the forwarding plane. If bit errors occur on all trunk member interfaces or the number of member interfaces without bit errors is lower than the lower threshold for the trunk interface's Up links, bit-error-triggered protection switching involves the following modes:

Trunk-bit-error-triggered section switching: The trunk interface goes Down, triggering an upper-layer application associated with the trunk interface to perform a service switchover.
Trunk-bit-error-triggered IGP route switching: The trunk interface ignores the bit errors on the member interfaces and remains Up. However, the link quality level of the trunk interface becomes Low, triggering an IGP to increase the cost of the trunk interface's link. IGP routes then do not preferentially select the link.

If bit errors occur on the trunk interfaces on both the primary and secondary links, trunk-bit-error-triggered section switching may interrupt services. Therefore, trunk-bit-error-triggered IGP route switching is recommended.

Pre-configuration Tasks

Before configuring bit-error-triggered trunk update, complete the following tasks:

Configure an Eth-Trunk interface in manual load balancing mode or configure an Eth-Trunk interface in static LACP mode.
Enable BFD globally.

If trunk-bit-error-triggered IGP route switching is configured, complete either of the following tasks based on a used IGP:

Procedure

Enable bit error detection on each trunk member interface.
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The trunk member interface view is displayed.
3. Enable bit error detection, and configure bit error alarm thresholds on the interface.
  - If trunk-bit-error-triggered section switching is configured, run the trap-threshold crc-error packet-error-ratio alarm-threshold alarm-coe alarm-pow [ resume-threshold resume-coe resume-pow ] [ trigger-lsp | trigger-section ] command to enable bit error detection on the interface and set BER thresholds for triggering bit error alarms.
    
    To enable bit-error-triggered trunk update to take effect, you must specify the switching type, either trigger-lsp or trigger-section.
  - If trunk-bit-error-triggered IGP route switching is configured, run the link-quality low bit-error-threshold error-ratio trigger-coefficient trigger-power resume-ratio recovery-coefficient recovery-power command to enable bit error detection on the interface and set BER thresholds for determining link quality.
4. Run commit
  The configuration is committed.
Enable bit error detection on a trunk interface.
1. Run system-view
  The system view is displayed.
2. Run either of the following commands:
  - Run the interface eth-trunk trunk-id command to enter the view of an Eth-Trunk interface.
3. Run bit-error-detection
  Bit error detection is enabled on the trunk interface.
4. (Optional) If trunk-bit-error-triggered IGP route switching is configured, perform the following operations depending on a used IGP:
  If IS-IS is used:
  1. Run the isis enable [ process-id ] command to enable the IS-IS function on the interface.
  2. Run the isis link-quality low incr-cost { cost | max-reachable } command to enable the IS-IS interface to automatically adjust the link cost based on link quality.
  If OSPF is used:
  1. Run the ospf enable [ process-id ] area area-id command to enable the OSPF function on the interface.
  2. Run the ospf link-quality low incr-cost { cost | max-reachable } command to enable the OSPF interface to automatically adjust the link cost based on link quality.
5. Run commit
  The configuration is committed.