No spanning tree instance exists in 2960x switch

[mohammad saeed]

Hi guys,

I have brand new 2960x stack switch and I enabled PVST STP mode but when I make show spanning tree it gaves me No spanning tree instance exists.

What is the problem

Cisco IOS Software, C2960X Software (C2960X-UNIVERSALK9-M), Version 15.2(2)E3, RELEASE SOFTWARE (fc3)

Thanks

Mohammad

[Rolf Fischer]

Mohammad,

does the switch have any link in operational state? If not, this is normal behavior. For each VLAN, at least one link has to be operational to bring the associated STP instance up.

If, however, the switch has opertional links, could you share the output of "show vlan brief" and "show interface status" ?

HTH
Rolf

[mohammad saeed]

I connect it with core switch 6807 but the interface is down my native vlan is not 1! 

[Rolf Fischer]

Ok, so could you share the two interface-configs and "show interface <interface> status" of the 2960X and 6807 and the output of "show vlan brief" from the 2960X?

[mohammad saeed]

Core:

!
interface TenGigabitEthernet1/1/14
description ## 3F_IDF_1 ##
switchport
switchport mode trunk

!
interface TenGigabitEthernet2/1/14
description ## 3F_IDF_1 ##
switchport
switchport mode trunk

!
spanning-tree mode rapid-pvst
spanning-tree extend system-id
spanning-tree vlan 2-999 priority 24576

2960x:

the port connect core-1 is on error disable state and port connect to core 2 is not connect??? why?

thanks

Mohammad

[Rolf Fischer]

What is the reason for the error disable state ("show interfaces status err-disabled" / "show logging")?

[mohammad saeed]

Hi guys! After plenty of investigation I took the switch to DC and connected with core with Fiber patch cord and worked! so the problem was from fiber splicing ! but the strange issue is I was be able to see the laser light from both end but maybe the fiber is not good!

Thanks ;)

[mohammad saeed]

Now gave me the port tengig connect with core notconnect! 

I made mode trunk in both side and no shutdown

One stack switches working fine but a lot not working! why?

[abdelfettahmokadem]

Mohammad,

You have to create VLAN XX before entering the command "show spanning-tree vlan XX", that's all.