网络环路
华为交换下接普通交换机，接线环路报文，对应下接交换机端口可能会加快闪烁频率，并且交换机会有大量的BPDU报文
Apr 5 2022 05:05:43 FutureMatrix %%01MSTP/4/LOOPBACK_DETECTED(l)[4]:The port GigabitEthernet0/0/19 was blocked because it received the BPDU packets sent by itself. Apr 5 2022 05:05:43 FutureMatrix %%01MSTP/4/SET_PORT_DISCARDING(l)[5]:In MSTP process 0 instance 0, MSTP set port GigabitEthernet0/0/19 state as discarding. [FutureMatrix] Apr 5 2022 05:05:48 FutureMatrix LLDP/4/RATEEXCESSIVE:OID 1.3.6.1.4.1.56813.5.25.134.2.7 The rate of received PDUs exceeded the threshold. (IfName=GigabitEthernet0/0/19) [FutureMatrix] Apr 5 2022 05:05:53 FutureMatrix LLDP/4/NBRCHGTRAP:OID 1.0.8802.1.1.2.0.0.1 Neighbor information is changed. (LldpStatsRemTablesInserts=1, LldpStatsRemTablesDeletes=0, LldpStatsRemTablesDrops=0, LldpStatsRemTablesAgeouts=0) Apr 5 2022 05:05:53 FutureMatrix LLDP/4/RATEEXCESSIVE:OID 1.3.6.1.4.1.56813.5.25.134.2.7 The rate of received PDUs exceeded the threshold. (IfName=GigabitEthernet0/0/19) [FutureMatrix] Apr 5 2022 05:05:58 FutureMatrix LLDP/4/RATEEXCESSIVE:OID 1.3.6.1.4.1.56813.5.25.134.2.7 The rate of received PDUs exceeded the threshold. (IfName=GigabitEthernet0/0/19) [FutureMatrix] Apr 5 2022 05:06:04 FutureMatrix LLDP/4/RATEEXCESSIVE:OID 1.3.6.1.4.1.56813.5.25.134.2.7 The rate of received PDUs exceeded the threshold. (IfName=GigabitEthernet0/0/19)
此时可以在交换机全局启用loopback-detect enable，查看接口状态会显示#down ，并且从接口状态可以查看到带宽利用率达到了81.2%
GigabitEthernet0/0/19 #down down 81.22% 0% 0 0