STP Light Status

Hi all,

Correct me if I'm wrong but I always thought that blocked STP ports were always Amber, but after playing around with STP in my home lab I've noticed that the only Amber ports that actually show are any blocked ports connecting to the Root Bridge - The blocked ports on the segments not connected to the Root Bridge should in theory be Amber as well but they're all green?? Does anyone have an explanation for this?

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Comments

tech-airman

redgoblin wrote:

Hi all,

Correct me if I'm wrong but I always thought that blocked STP ports were always Amber, but after playing around with STP in my home lab I've noticed that the only Amber ports that actually show are any blocked ports connecting to the Root Bridge - The blocked ports on the segments not connected to the Root Bridge should in theory be Amber as well but they're all green?? Does anyone have an explanation for this?

redgoblin,

Which model switch are you talking about?

redgoblin

This happens on a 2950-12, 2950-24, and a 3550-PoE.

Weird thing is, on each of the switches above, the redundant connections directly to the Root Bridge show as Amber, but the the blocked ports on Segments not connected to the Root Bridge show as Green rather than Amber.

dtlokee

They will remain green if it's a trunk port because with PVST+ each VLAN can be blocked separately.

redgoblin

Yeah I 'm guessing you're right about PVST+ - But what I don't understand is I'm only using VLAN 1 and in any case, if PVST+ shows Blocked Ports as Green due to the possibility of the same ports being Forwarding in other VLANs, the direct 'Alternate' Root Port connections should've showed as green as well (since there's every possibility they could be Forwarding in other VLANs), but they show Amber?

Confused ..

dtlokee

Is it a trunk or access port?

show interface fa x/y switchport

redgoblin

All dot1q Trunks

ITdude

redgoblin wrote:

All dot1q Trunks

There you go....