Symptom

Catalyst 3650, 3850, 9300, and 9500 with uplink modules, or Catalyst 9400 modular switches running the impacted code versions will allocate hardware buffers to non-active ports. Symptoms include: Traffic loss on 40G port when "enable/no enable" of corresponding 100G ports Policy shape/QoS not working on impacted uplink modules or line cards Traffic loss on traffic that ingresses and egresses on the same uplink module or line card

Conditions

Hardware buffers being allocated to non-active ports. For example, a Catalyst 9300 with a C9300-NM-2Y uplink module. The C9300-NM-2Y only supports the two twenty gig ports, TwentyFiveGigE1/1/1 and TwentyFiveGigE1/1/2. Checking the hardware queuing structure will show buffer allocations for the unused gig and forty gig ports: C9300# show platform hardware fed switch 1 qos queue config interf forty 1/1/2 >>>>>>>>>>>>>>>>>>>. 40G non-active ports DATA Port:37 GPN:0 AFD:Disabled FlatAFD:Disabled QoSMap:0 HW Queues: 296 - 303 DrainFast:Disabled PortSoftStart:6 - 30000 ---------------------------------------------------------- DTS Hardmax Softmax PortSMin GlblSMin PortStEnd ----- -------- -------- -------- -------- --------- 0 1 7 2136 15 30000 4 3750 0 0 3 30000 1 1 4 0 15 30000 6 5625 3 2812 3 30000 2 1 4 0 5 0 0 0 0 0 3 30000 3 1 4 0 5 0 0 0 0 0 3 30000 4 1 4 0 5 0 0 0 0 0 3 30000 5 1 4 0 5 0 0 0 0 0 3 30000 6 1 4 0 5 0 0 0 0 0 3 30000 7 1 4 0 5 0 0 0 0 0 3 30000 Priority Shaped/shared weight shaping_step sharpedWeight -------- ------------- ------ ------------ ------------- 0 0 Shared 50 0 0 1 0 Shared 75 0 0 2 0 Shared 10000 0 0 3 0 Shared 10000 0 0 4 0 Shared 10000 0 0 5 0 Shared 10000 0 0 6 0 Shared 10000 0 0 7 0 Shared 10000 0 0

Workaround

Move impacted ports off of uplink module or line cards

Further Problem Description