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Hello all,
Every 15min and sometimes every half an hour I get this message in my log file of N2048 series switch.
<189> Nov 20 14:47:52 d3sw1-1 TRAPMGR[dot1s_task]: traputil.c(795) 84096054 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Gi1/0/48
<189> Nov 20 14:47:50 d3sw1-1 TRAPMGR[dot1s_task]: traputil.c(795) 84095826 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Gi1/0/48
Does that mean there is a loop somewhere? Where should I start troubleshooting this?
d3sw1(config)#show spanning-tree mst-configuration
Name: F8-34-56-50-2B-11
Revision: 0
Instance Vlan Mapped
---------- -----------------------------------------------
0 1,15,25,32,34,100,212,236,3034-3065,3108,3128-3129,3500-3502,3560,3570,3576,3592,3594,3970
----------------------------------------------------------
d3sw1(config)#show spanning-tree
Spanning Tree : Enabled
BPDU Flooding : Disabled
Mode : mst
Portfast BPDU Filtering : Disabled
Portfast BPDU Guard : Disabled
CST Regional Root : 80:00:F8:B1:56:50:2B:10
Regional Root Path Cost : 0
###### MST 0 Vlan Mapped: 1,15,25,32,34,100,212,236,3034-3065,3108,3128-3129,3500-3502,3560,3570,3576,3592,3594,3970
ROOT ID
Priority 16384
Address 0C29.EFSD.1D20
Path Cost 43383
Root Port Gi1/0/48
Hello Time: 2s Max Age: 20s Forward Delay: 15s Transmit Hold Count: 6s
Bridge Max Hops: 20
Bridge ID
Priority 32768
Address F8B1.6658.2411
Hello Time: 2s Max Age: 20s Forward Delay: 15s Transmit Hold Count: 6s
Name State Prio.Nbr Cost Sts Role RestrictedPort
--------- -------- --------- --------- ---- ----- --------------
Gi1/0/1 Enabled 128.1 0 DIS Disb No
Gi1/0/2 Enabled 128.2 0 DIS Disb No
Gi1/0/3 Enabled 128.3 0 DIS Disb No
Gi1/0/4 Enabled 128.4 0 DIS Disb No
Gi1/0/5 Enabled 128.5 0 DIS Disb No
Gi1/0/6 Enabled 128.6 0 DIS Disb No
Gi1/0/7 Enabled 128.7 0 DIS Disb No
Gi1/0/8 Enabled 128.8 0 DIS Disb No
Gi1/0/9 Enabled 128.9 0 DIS Disb No
Gi1/0/10 Enabled 128.10 20000 FWD Desg No
Gi1/0/11 Enabled 128.11 20000 FWD Desg No
Gi1/0/12 Enabled 128.12 20000 FWD Desg No
Gi1/0/13 Enabled 128.13 20000 FWD Desg No
Gi1/0/14 Enabled 128.14 20000 FWD Desg No
Gi1/0/15 Enabled 128.15 20000 FWD Desg No
Gi1/0/16 Enabled 128.16 20000 FWD Desg No
Gi1/0/17 Enabled 128.17 20000 FWD Desg No
Gi1/0/18 Enabled 128.18 20000 FWD Desg No
Gi1/0/19 Enabled 128.19 0 DIS Disb No
Gi1/0/20 Enabled 128.20 0 DIS Disb No
Gi1/0/21 Enabled 128.21 0 DIS Disb No
Gi1/0/22 Enabled 128.22 0 DIS Disb No
Gi1/0/23 Enabled 128.23 0 DIS Disb No
Gi1/0/24 Enabled 128.24 0 DIS Disb No
Gi1/0/25 Enabled 128.25 0 DIS Disb No
Gi1/0/26 Enabled 128.26 0 DIS Disb No
Gi1/0/27 Enabled 128.27 0 DIS Disb No
Gi1/0/28 Enabled 128.28 0 DIS Disb No
Gi1/0/29 Enabled 128.29 0 DIS Disb No
Gi1/0/30 Enabled 128.30 0 DIS Disb No
Gi1/0/31 Enabled 128.31 0 DIS Disb No
Gi1/0/32 Enabled 128.32 0 DIS Disb No
Gi1/0/33 Enabled 128.33 0 DIS Disb No
Gi1/0/34 Enabled 128.34 0 DIS Disb No
Gi1/0/35 Enabled 128.35 0 DIS Disb No
Gi1/0/36 Enabled 128.36 0 DIS Disb No
Gi1/0/37 Enabled 128.37 0 DIS Disb No
Gi1/0/38 Enabled 128.38 0 DIS Disb No
Gi1/0/39 Enabled 128.39 20000 FWD Desg No
Gi1/0/40 Enabled 128.40 20000 FWD Desg No
Gi1/0/41 Enabled 128.41 20000 FWD Desg No
Gi1/0/42 Enabled 128.42 0 DIS Disb No
Gi1/0/43 Enabled 128.43 20000 FWD Desg No
Gi1/0/44 Enabled 128.44 20000 FWD Desg No
Gi1/0/45 Enabled 128.45 0 DIS Disb No
Gi1/0/46 Enabled 128.46 20000 FWD Desg No
Gi1/0/47 Enabled 128.47 0 DIS Disb No
Gi1/0/48 Enabled 128.48 20000 FWD Root No
Te1/0/1 Enabled 128.49 0 DIS Disb No
Te1/0/2 Enabled 128.50 0 DIS Disb No
----------------------------------------------------------------
Any ideas/suggestions please? Do you see anything wrong in my config?
Many thanks
DELL-Charles R
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Posted November 20th, 2023 21:52
Hello,
Have you confirmed you are on the latest Firmware Version 6.7.1.22?
Check your cabling for Gi1/0/48, reseat or try another cable if you have one.
We can see that port Gi1/0/48 is a root port so that means it is connected to another switch.
The Topology Change Notification (TCN) is received from the other switch on port Gi1/0/48.
To prevent topology changes and TCNs from occurring, it is recommended to use portfast on access ports that connect to end devices, such as PCs, servers, or printers, that allows them to transition directly to the forwarding state, reducing the STP convergence time.
When a PC is powered up (for example someone comes to work in the morning and powers up the PC, or there is a device that reboots) and TCN is sent across all switches notifying of this spanning-tree change. If portfast/edgeport is configured on that port, a TCN will not be sent.
So the switch that is connected on port gi1/0/48 should have portfast / edgeport configured on all interfaces except the interfaces that connect to switches. Sometimes if there are multiple switches interconnected the TCN can come from any one of these switches.
CLI Reference Guide Version 6.7
https://dell.to/49IVSfW
Spanning Tree page 814
Spanning-tree portfast page 846
DELL-Charles R
Social Media and Communities Professional
Dell Technologies | Enterprise Support Services
#IWork4Dell
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