After S7500X was connected with CS, the CS interface was error-disabled

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fter replacing the S5560EI, the S7503X is connected to the CS MSTP, but the CS device port is blocked.The aggregation port 4 of our device is connected to the aggregation port 4 of CS.

When CS configuring No Spann BPDuFilter to filter out the BPDU we sent, the solution will be solved.

The customer suspected that CS had a problem with our MSTP.

spanning-tree mst configuration

name py.dwgl.grcb

revision 1

stp region-configuration

region-name py.dwgl.grcb

revision-level 1

active region-configuration

Here"s why CS is blocking:

Cisio devoce received two BPDU"s from the interface connected to our 7500X, one for the configuration BPDU and one for the TC BPDU:

PYDC_2FN06_DaiW_AS29(config-if)#

PYDC_2FN06_DaiW_AS29(config-if)#TP: MST0 rx BPDU: config protocol = mstp, packet from Port-channel1  , linktype SSTP , enctype 3, encsize 22

*Aug  6 17:31:18.173: STP: enc 01 00 0C CC CC CD 88 75 56 DC E4 B1 00 32 AA AA 03 00 00 0C 01 0B

*Aug  6 17:31:18.173: STP: Data     000000000182C6887556DCE4800000000082C6887556DCE48080380000140002000F00

*Aug  6 17:31:18.173: STP: MST0 Po1:0000 00 00 01 82C6887556DCE480 00000000 82C6887556DCE480 8038 0000 1400 0200 0F00

*Aug  6 17:31:18.173: STP: MST0 rx BPDU: config protocol = mstp, packet fr

PYDC_2FN06_DaiW_AS29(config-if)#om Port-channel1  , linktype SSTP , enctype 3, encsize 22

*Aug  6 17:31:18.173: STP: enc 01 00 0C CC CC CD 88 75 56 DC E4 B1 00 32 AA AA 03 00 00 0C 01 0B

*Aug  6 17:31:18.173: STP: Data     000000000182C7887556DCE4800000000082C7887556DCE48080380000140002000F00

*Aug  6 17:31:18.173: STP: MST0 Po1:0000 00 00 01 82C7887556DCE480 00000000 82C7887556DCE480 8038 0000 1400 0200 0F00

*Aug  6 17:31:19.440: STP: MST0 rx BPDU: config protocol = mstp, packet from Port-channel1  , linktype IEEE_SPANNING , enctyp

PYDC_2FN06_DaiW_AS29(config-if)#e 2, encsize 17

*Aug  6 17:31:19.440: STP: enc 01 80 C2 00 00 00 00 0F E2 07 F2 E0 00 69 42 42 03

*Aug  6 17:31:19.440: STP: Data     000003023C0000101965CAAE00000000000000101965CAAE0088DD0000140002000F00

*Aug  6 17:31:19.448: STP: MST0 Po1:0000 03 02 3C 0000101965CAAE00 00000000 0000101965CAAE00 88DD 0000 1400 0200 0F00

*Aug  6 17:31:20.178: %PM-4-ERR_DISABLE: channel-misconfig error detected on Gi0/3, putting Gi0/3 in err-disable state

*Aug  6 17:31:20.178: %PM-4-ERR_DISABLE: channel-misconfig

PYDC_2FN06_DaiW_AS29(config-if)# error detected on Gi0/4, putting Gi0/4 in err-disable state

*Aug  6 17:31:20.186: %PM-4-ERR_DISABLE: channel-misconfig error detected on Po1, putting Gi0/3 in err-disable state

*Aug  6 17:31:20.186: %PM-4-ERR_DISABLE: channel-misconfig error detected on Po1, putting Gi0/4 in err-disable state

*Aug  6 17:31:20.186: %PM-4-ERR_DISABLE: channel-misconfig error detected on Po1, putting Po1 in err-disable state

*Aug  6 17:31:21.184: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/3, changed state to down

*Aug  6 17:31:21.184: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/4, changed state to down

*Aug  6 17:31:21.193: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel1, changed state to down

*Aug  6 17:31:22.191: %LINK-3-UPDOWN: Interface GigabitEthernet0/3, changed state to down

*Aug  6 17:31:22.191: %LINK-3-UPDOWN: Interface Port-channel1, changed state to down

*Aug  6 17:31:22.191: %LINK-3-UPDOWN: Interface GigabitEthernet0/4, changed state to downno spann  bpduf

PYDC_2FN06_DaiW_AS29(config-if)#no spann  bpdufilter

*Feb  7 09:49:20:042 2021 PYDC_2FN08_DWGL_DS7503_IRF STP/7/PKT: -MDC=1;

Port18653(Bridge-Aggregation4) sent MSTP-dot1s Packet(Length: 102)

ProtocolVersionID: 03

BPDUType         : 02

CIST Root ID     : 0.1019-65ca-ae00

External RPC     : 0     

Reg Root ID      : 0.1019-65ca-ae00

Internal RPC     : 0      

CIST Bridge ID   : 0.1019-65ca-ae00

CIST Port ID     : 128.2269

(Instance)Flags  : (00)Desi[  FL  ] 

%Feb  7 09:49:20:939 2021 PYDC_2FN08_DWGL_DS7503_IRF STP/6/STP_DETECTED_TC: -MDC=1; Instance 0"s port Bridge-Aggregation4 detected a topology change.

*Feb  7 09:49:20:940 2021 PYDC_2FN08_DWGL_DS7503_IRF STP/7/PKT: -MDC=1;

Port18653(Bridge-Aggregation4) received STP Packet(Length: 35)

ProtocolVersionID: 00

BPDUType         : 00

Root ID          : 32768.f025-72fc-1a80

Path Cost        : 0      

Bridge ID        : 32768.f025-72fc-1a80

Port ID          : 128.56

Flags            : [Tc]

After receiving the STP message from CS, our device establishes itself as the root bridge and sends packets all the time without receiving the message from the opposite end. At this time, the state of the opposite end is already dispute

*Feb  7 09:44:49:625 2021 PYDC_2FN08_DWGL_DS7503_IRF STP/7/PKT: -MDC=1;

Port18653(Bridge-Aggregation4) received MSTP-dot1s Packet(Length: 102)

ProtocolVersionID: 03

BPDUType         : 02

CIST Root ID     : 0.1019-65ca-ae00

External RPC     : 0      

Reg Root ID      : 0.1019-65ca-ae00

Internal RPC     : 10000  

CIST Bridge ID   : 32768.f025-72fc-1a80

CIST Port ID     : 128.56

(Instance)Flags  : (00)Root[ A   Tc] 

%Feb  7 09:44:49:625 2021 PYDC_2FN08_DWGL_DS7503_IRF STP/6/STP_NOTIFIED_TC: -MDC=1; Instance 0"s port Bridge-Aggregation4 was notified a topology change.

Cisco"s equipment on Channel1 received two STP messages at the same time, one was the MSTP sent by us, the other was the PVST sent by MAC 8875-56DC-E480, so they were disabled.

*Aug  6 17:39:12.431: STP: MST0 rx BPDU: config protocol = mstp, packet from Port-channel1  , linktype IEEE_SPANNING , enctype 2, encsize 17

*Aug  6 17:39:12.431: STP: enc 01 80 C2 00 00 00 00 0F E2 07 F2 E0 00 26 42 42 03

*Aug  6 17:39:12.431: STP: Data     00000000000000101965CAAE00000000000000101965CAAE0088DD0000140002000F00

*Aug  6 17:39:12.431: STP: MST0 Po1:0000 00 00sh  00 0000101965CAAE00 00000000 0000101965CAAE00 88DD 0000 1400 0200 0F00

*Aug  6 17:39:12.607: STP: MST0 rx BPDU: config protocol = mstp, packet from Port-channel1  , linktype SSTP , enctype 3, encsize 22

*Aug  6 17:39:12.607: STP: enc 01 00 0C CC CC CD 88 75 56 DC E4 B1 00 32 AA AA 03 00 00 0C 01 0B

*Aug  6 17:39:12.616: STP: Data     000000000182C6887556DCE4800000000082C6887556DCE48080380000140002000F00

We configure STP pvst-bpdu-protection command on our device, which will down the port receiving PVST message, and then we can see the PVST message received by that interface.

It is also recommended to find the 8875-56DC-E480 equipment.