The switch went offline today

Hi Experts,

I have a cisco 3750x 48 POE port, it went offline for about 2 minutes and came back online, I'm looking for the reason it went offline and the code is 'show log' .

and here is  configure of the trunking port:

interface GigabitEthernet1/0/48
 switchport trunk encapsulation dot1q
 switchport mode trunk
 storm-control broadcast level 40.00
end

 Any ideas why it went offline? Thanks.
SouthSwitch#sh log
Dec  6 20:57:32.354: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 1 on GigabitEthernet1/0/48 VLAN45.
Dec  6 20:57:32.363: %SPANTREE-2-BLOCK_PVID_PEER: Blocking GigabitEthernet1/0/48 on VLAN0001. Inconsistent peer vlan.
Dec  6 20:57:32.363: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking GigabitEthernet1/0/48 on VLAN0045. Inconsistent local vlan.
Dec  6 20:57:32.380: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
Dec  6 20:59:47.667: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/48 on VLAN0001. Port consistency restored.
Dec  6 20:59:47.667: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/48 on VLAN0045. Port consistency restored.
Dec  6 21:00:17.689: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up

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SJCAAsked:
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mr_dirtCommented:
Did the entire switch become unavailable, or only connectivity through the port indicated in the message (GigabitEthernet1/0/48)?  What sort of host is connected on the port that the error message names?

Was someone working in the wiring closet where the switch is and possibly correct a cable incorrectly, or did someone reboot or reconfigure the device connected on that switchport?

This message means that the switch picked up a spanning-tree notification from an adjacent device that doesn't match the expected VLAN tagging configuration.  The adjacent device may have been another switch, or may have been a server that has enough smarts in the network interface to participate in spanning-tree.

What is the spanning-tree configuration on the 3750X?  What does the rest of your network look like?
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SJCAAuthor Commented:
The port g1/0/48 is single uplink for that switch (switch A). When it was offline, I could not ping to it.

I don't think anyone was working on that wiring closet since it's locked and only me and my boss have the key.

>The adjacent device may have been another switch, or may have been a server that has enough smarts in the network interface to participate in spanning-tree.

I have a new switch 3750x (Switch C) which powered up today and connected to the core switch on port 48, the switch A went offline right after that the switch C powered up. The core switch port 48 was configured to access VLAN45, when I realized that is not the right configuration I changed it to trunking port and both switch A and C have been online since. I also checked the new switch and found out that the new switch (switch C) which has the same error log like switch A above. All the switches should be on vlan 1. You're right, the switch A picked up spanning-tree notification from an adjacent device (switch C) that's why it went offline until I changed the port 48 on core switch to trunking.

Core switch --> switch B ---> switch A
       |
       |
  switch C

By default, Cisco 3750x has spanning tree enable on every interface but not on the trunking port right?




SouthSwitch#sh spanning-tree

VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    0
             Address     001a.c13b.1280
             Cost        39
             Port        48 (GigabitEthernet1/0/48)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     70ca.9bf5.5000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/48            Root FWD 19        128.48   P2p



VLAN0002
  Spanning tree enabled protocol ieee
  Root ID    Priority    32771
             Address     0018.badf.0ec0
             Cost        19
             Port        48 (GigabitEthernet1/0/48)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32771  (priority 32768 sys-id-ext 3)
             Address     70ca.9bf5.5000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1             Desg FWD 19        128.1    P2p Edge
Gi1/0/2             Desg FWD 19        128.2    P2p Edge
Gi1/0/3             Desg FWD 19        128.3    P2p Edge
Gi1/0/5             Desg FWD 19        128.5    P2p Edge
Gi1/0/14            Desg FWD 19        128.14   P2p Edge
Gi1/0/15            Desg FWD 19        128.15   P2p Edge
Gi1/0/16            Desg FWD 19        128.16   P2p Edge

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

Gi1/0/17            Desg FWD 19        128.17   P2p Edge
Gi1/0/48            Root FWD 19        128.48   P2p



VLAN0045
  Spanning tree enabled protocol ieee
  Root ID    Priority    32813
             Address     70ca.9bf5.5000
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32813  (priority 32768 sys-id-ext 45)
             Address     70ca.9bf5.5000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/15            Desg FWD 19        128.15   P2p Edge
Gi1/0/48            Desg FWD 19        128.48   P2p



VLAN010
  Spanning tree enabled protocol ieee
  Root ID    Priority    32976
             Address     0007.7dc3.c000
             Cost        19
             Port        48 (GigabitEthernet1/0/48)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32976  (priority 32768 sys-id-ext 208)
             Address     70ca.9bf5.5000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/48            Root FWD 19        128.48   P2p



VLAN015
  Spanning tree enabled protocol ieee
  Root ID    Priority    32977
             Address     0007.7dc3.be80
             Cost        19
             Port        48 (GigabitEthernet1/0/48)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32977  (priority 32768 sys-id-ext 209)
             Address     70ca.9bf5.5000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1             Desg FWD 19        128.1    P2p Edge
Gi1/0/2             Desg FWD 19        128.2    P2p Edge
Gi1/0/3             Desg FWD 19        128.3    P2p Edge
Gi1/0/5             Desg FWD 19        128.5    P2p Edge
Gi1/0/14            Desg FWD 19        128.14   P2p Edge
Gi1/0/16            Desg FWD 19        128.16   P2p Edge
Gi1/0/17            Desg FWD 19        128.17   P2p Edge

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

Gi1/0/48            Root FWD 19        128.48   P2p



VLAN016
  Spanning tree enabled protocol ieee
  Root ID    Priority    32979
             Address     7081.055e.ef80
             Cost        19
             Port        48 (GigabitEthernet1/0/48)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32979  (priority 32768 sys-id-ext 211)
             Address     70ca.9bf5.5000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/4             Desg FWD 4         128.4    P2p Edge
Gi1/0/48            Root FWD 19        128.48   P2p



VLAN020
  Spanning tree enabled protocol ieee
  Root ID    Priority    33169
             Address     0007.7dc3.be80
             Cost        19
             Port        48 (GigabitEthernet1/0/48)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    33169  (priority 32768 sys-id-ext 401)
             Address     70ca.9bf5.5000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/7             Desg FWD 19        128.7    P2p Edge
Gi1/0/8             Desg FWD 19        128.8    P2p Edge
Gi1/0/9             Desg FWD 19        128.9    P2p Edge
Gi1/0/10            Desg FWD 19        128.10   P2p Edge
Gi1/0/11            Desg FWD 19        128.11   P2p Edge
Gi1/0/12            Desg FWD 19        128.12   P2p Edge
Gi1/0/13            Desg FWD 19        128.13   P2p Edge

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

Gi1/0/48            Root FWD 19        128.48   P2p

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akalbfellCommented:
Sounds like when you connected that new switch the network converged.
Can you show the output of these commands?

Sh spanning-tree Summary
Sh spanning-tree root

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mr_dirtCommented:
SJCA, to your question, "By default, Cisco 3750x has spanning tree enable on every interface but not on the trunking port right?", the answer is no.  Spanning tree is especially critical on trunks, because they carry multiple VLANs.  A switch must determine the spanning-tree topology for every VLAN it carries (as you can see from the "sh spanning-tree" output that you posted), which means that a trunk that carries multiple VLANs will cause the switch to negotiate STP on all VLANs it carries when the trunk comes up and detects a neighbor that runs STP.

Can you get the "show log" output from the core switch from when the VLANs were blocked?

Are you running Rapid PVST?  Are any of the switches configured as the spanning-tree root for any of your VLANs?

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SJCAAuthor Commented:
Will get these infos for you next week. Thanks.
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