03-09-2009 09:46 AM - edited 03-06-2019 04:29 AM
We have 3550 switch that is connected to another HP 2524 switch. On the 2524 switch we have several PCs that are on different VLANS. After a power off and on of the 3550, the PC are acting very strange. One might be able to access the Internet but not the Intranet, another may be exactly the opposite but be on the same VLAN. As soon as we remove the 2524 swith and put a hub in place all it well with all PCs on each VLAN. We put in an unmanaged Allied Telesyn switch and the PC act strange again. Below is the configuration of the port the HP or Allied switches are being plugged into.
switchport access vlan dynamic
switchport trunk encap dot1q
switchport trunk native vlan 2
switchport mode trunk
switchport nonegotiate
spanning-tree portfast
This is the running config on the 3550 is exactly the same as before it was powered off.
I am desperate for a resolution.
Solved! Go to Solution.
03-09-2009 10:11 AM
"Can it be changed on just that one port such as
switchport trunk native vlan 1"
Yes altho the default native vlan is vlan 1 anyway so under the interface
int fa0/13
no switchport trunk native vlan 2
then do a "sh int trunk" again and you should see native vlan as 1.
If you're unsure just post "sh int trunk" again after executing the command.
Jon
03-09-2009 09:51 AM
Ronald
Firstly you shouldn't have "spanning-tree portfast" on this link.
Are you seeing any log messages on the 3550.
Can you post the output of "sh int trunk".
The vlans that are on the 2524 switch, which switch is the STP root for these vlans.
You have a native vlan of 2 - is this what has been set on the other switch.
Jon
03-09-2009 09:57 AM
Here is the output of sho int trunk
Port Mode Encapsulation Status Native vlan
Fa0/13 on 802.1q trunking 2
Fa0/19 on 802.1q trunking 2
Gi0/1 desirable n-isl trunking 1
Port Vlans allowed on trunk
Fa0/13 1-4094
Fa0/19 1-4094
Gi0/1 1-4094
Port Vlans allowed and active in management domain
Fa0/13 1-6,8,34,234
Fa0/19 1-6,8,34,234
Gi0/1 1-6,8,34,234
Port Vlans in spanning tree forwarding state and not pruned
Fa0/13 1-6,8,34,234
Fa0/19 1-6,8,34,234
Gi0/1 1-6,8,34,234
I am sorry, the HP switch was an unmanaged switch as well, a HP 2124. It is plugged into Fa0/13 on the 3550
03-09-2009 10:01 AM
If it's unmanaged it is unlikely to be using vlan 2 as it's native vlan. Can you change the native vlan to vlan 1 on your 3550.
Are you seeing anything in the logs.
Jon
03-09-2009 10:07 AM
I can test the native VLAN. Can it be changed on just that one port such as
switchport trunk native vlan 1
Here is what is in my log file.
000163: Mar 5 20:36:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEth ernet0/13, changed state to up
000164: Mar 5 20:36:27: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsist ent peer vlan id 1 on FastEthernet0/11 VLAN2.
000165: Mar 5 20:36:27: %SPANTREE-2-BLOCK_PVID_PEER: Blocking FastEthernet0/13 on VLAN0001. Inconsistent peer vlan.
000166: Mar 5 20:36:27: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking FastEthernet0/13 on VLAN0002. Inconsistent local vlan.
000167: Mar 5 20:36:42: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthern et0/13 on VLAN0001. Port consistency restored.
000168: Mar 5 20:36:42: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthern et0/13 on VLAN0002. Port consistency restored.
000169: Mar 5 20:41:11: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEth ernet0/11, changed state to down
03-09-2009 10:11 AM
"Can it be changed on just that one port such as
switchport trunk native vlan 1"
Yes altho the default native vlan is vlan 1 anyway so under the interface
int fa0/13
no switchport trunk native vlan 2
then do a "sh int trunk" again and you should see native vlan as 1.
If you're unsure just post "sh int trunk" again after executing the command.
Jon
03-09-2009 10:17 AM
Ok, I will give those options a try and report back as soon as I can.
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