Licensing Requirements and Limitations for Congestion Avoidance and Congestion Management

Involved Network Elements

Other network elements are not required.

Licensing Requirements

Congestion management and congestion avoidance are basic features of a switch and are not under license control.

Version Requirements

For details about the mapping between software versions and switch models, see the Hardware Query Tool.

Software version evolution: V100R001C00 -> V100R002C00 -> V100R003C00 -> V100R003C10 -> V100R005C00 -> V100R005C10 -> V100R006C00 -> V200R001C00 -> V200R002C50 -> V200R003C00 -> V200R005C00 -> V200R005C10 -> V200R019C00 -> V200R019C10

Feature Limitations

Limitations on Congestion Avoidance

• Congestion avoidance is valid for only known unicast packets.
• If you apply a WRED drop profile to an interface and an interface queue simultaneously, the WRED drop profile that is applied to the interface queue first takes effect.
• In the following scenarios, ECN threshold may fail to be triggered when a queue is congested, and does not take effect.
  • The configured threshold for ECN is too high.
  • The configured queue buffer threshold is too low.
  • The burst traffic buffer mode is set to low-latency.

Limitations on Congestion Management

• For the CE12800: Congestion management is valid for only known unicast traffic.
• A device interface supports PQ, WFQ, and PQ+WFQ for congestion management on the CE12800.
• A device interface supports PQ, DRR, and PQ+DRR for congestion management on the CE12800E configured with ED-E, EG-E, and EGA-E series cards.
• A device interface supports PQ, DRR, PQ+DRR, WRR, and PQ+WRR for congestion management on the CE12800E configured with FD-X series cards.

Limitations on Queue-based Traffic Statistics

• For the CE12800: In an earlier version of V200R003C00 uses the traffic statistics function to count known unicast packets on the outbound interface, the statistics on discarded packets include the packets that are discarded because MQC-based traffic policing, hierarchical traffic policing, traffic suppression, and storm control are applied in the inbound direction. There is no such a limitation for SD, FD, FD1, FDA, FG, and FG1 series card in V200R003C00 and later versions.

Limitations When Congestion Avoidance and Congestion Management Are Used with Other Services

• Global ECN cannot be enabled in a VS except the Admin-VS in port mode, whereas global ECN that is enabled in the Admin-VS takes effect in other VSs in port mode. Global ECN can be enabled in a VS in port group mode and takes effect only in this VS.
• The device can be enabled to generate an alarm when the queue buffer exceeds the threshold only in the Admin-VS. The configured alarm function is valid for all VSs.