OPERATIONAL DEFECT DATABASE
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"random-detect threshold burst-optimized" configured under class type queuing c-out-8q-q-default" is causing drops on the interface where this service policy is applied. "random-detect threshold burst-optimized ecn" will cause the same issue.
N9K FX3/GX Issue is seen on 10.2(5) and prior 10.2(x) releases and on 10.3(3) and prior 10.3(x). Issue is not seen on 9.3(x). "random-detect threshold burst-optimized" is configured under "class type queuing c-out-8q-q-default".
remove "random-detect threshold burst-optimized".
[+]Sample QoS that can cause the issue: N9K-C93180YC-FX3-1# show policy-map type queuing TEST_POLICY_TAC Type queuing policy-maps ======================== policy-map type queuing TEST_POLICY_TAC class type queuing c-out-8q-q7 priority level 1 queue-limit dynamic 4 class type queuing c-out-8q-q6 bandwidth remaining percent 0 class type queuing c-out-8q-q5 bandwidth remaining percent 0 class type queuing c-out-8q-q4 bandwidth remaining percent 0 class type queuing c-out-8q-q3 bandwidth remaining percent 0 class type queuing c-out-8q-q2 bandwidth remaining percent 0 class type queuing c-out-8q-q1 bandwidth remaining percent 0 class type queuing c-out-8q-q-default bandwidth remaining percent 100 random-detect threshold burst-optimized <<<<<< [+]Service policy applied under the interface: N9K-C93180YC-FX3-1# show running-config interface e1/50 !Command: show running-config interface Ethernet1/50 !Running configuration last done at: Thu Jul 20 15:57:40 2023 !Time: Thu Jul 20 16:21:14 2023 version 10.2(5) Bios:version 01.08 interface Ethernet1/50 switchport switchport mode trunk switchport trunk allowed vlan 203,253,501,551,613,701 service-policy type queuing output TEST_POLICY_TAC no shutdown [+]Drop seen on the interface: N9K-C93180YC-FX3-1# show queuing interface ethernet 1/50 +-------------------------------------------------------------+ | QOS GROUP 0 | +-------------------------------------------------------------+ | | Unicast |Multicast | +-------------------------------------------------------------+ | Tx Pkts | 0| 0| | Tx Byts | 0| 0| | WRED/AFD & Tail Drop Pkts | 36| 0| <<<<<<<<<< | WRED/AFD & Tail Drop Byts | 5016| 0| <<<<<<<<<< | Q Depth Byts | 0| 0| +-------------------------------------------------------------+
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