STP blocking but status led green

[fsoffia]

hallo

I have some cat2950 with ios 12.1.22EA7 connected toghether with 3 VLAN and STP (PVST) configured.

On redundant links the STP shows correctly the blocking state of the interfaces but the STATUS LEDs are GREEN not amber.

The configs and the tree seems ok, the only strange thing is green leds !!

Could it be an ios bug or a config problem ?

francesco

[mahmoodmkl]

HI

I think this is the natural behaviour becoz the blocking is done logically. but the bolcked port is going to revieve the BPDU's but does not process them.so as it is reciveing some sort of traffic it is going to be green only.if the interface is having any problem then it may go in the amber state.

Thanks

Mahmood

[Marvin Rhoads]

I'm not sure this is normal as the earlier poster asserted. See http://www.cisco.com/en/US/partner/products/hw/switches/ps605/products_installation_guide_chapter09186a00800d9cfe.html#39834 for details on what the status LEDs mean. The relevant text is in Table 1-6:

/quote

Solid amber:

Port is not forwarding. Port was disabled by management or an address violation or was blocked by Spanning Tree Protocol (STP).

Note After a port is reconfigured, the port LED can remain amber for up to 30 seconds as STP checks the switch for possible loops.

/end quote

An STP blocking port is still active and functional, just not passing trafic. It needs to have Ethernet link to communicate in the spanning tree process in the event that it needs to change state. BUT, as the manual says, if it is STP blocking, it should be amber

Hope this helps. Please rate helpful posts.

[fsoffia]

hallo

I agree with you.

The status led should be AMBER but it is GREEN on all the swithes that has the ports in blocking state.

The tree exist and is as expected but all the leds are green !!

The ios is c2950-i6q4l2-mz.121-22.EA7.bin

francesco

[nathan.a.reeves]

Are your ports set to trunk? If they are set to trunk using dot1q encapsulation, the interface status LED will be green and not amber. The status light would be amber if your port is not set to trunk and there was a STP block in operation on the port.

[fsoffia]

hi nathan

yes the ports are 802.1q trunks, there are vlans !

The trunk mode is auto negotiated by default.

You could be right.

I did not find any doc where is written that redundant trunks in blocking state have a green led and not amber.

Do you have a reference ?

thankyou

francesco

[rgodden]

is the port blocking for all vlans on the port ?

[fsoffia]

yes

in blocking for all vlans

francesco

[jv]

The link you provided is for a 2900XL switch, not a 2950 switch, they have different hardware and work differently.

[Marvin Rhoads]

Re the link, here is a link to the _2950_ hardware installation guide:

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat2950/12122eab/2950hig/hgovrev.htm

The text in tables 1-6 and 1-7 also seem to indicate that a STP blocking port's port status LED should be solid amber.

[jbrunner]

i think this happens alot when a vlan is not allowed on the trunk

switchport trunk allowed vlan 5,10,15,20

(like vlan 1)

so it will be forwarding, when it would normally be blocking on a backup trunk

[fsoffia]

hi I don't understand what do you mean...

The backup trunks allow all the vlans.

All the vlans are in blocking and I think this is correct but the leds are green !

francesco