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New Member

spanning tree

Hi all, if I have spanning tree turned off on all my uplinks, am i right in saying, no switch will send spanning tree bpdu's to the neighbour switch? and so also each switch will assume its the root?

8 REPLIES
New Member

Re: spanning tree

Wrong. Turning off spanning tree will NOT stop BPDU from being sent out. What it will do is the switch will NOT check for Layer-2 loop. So, let's say you link up 2 switches with a trunk link, and you turn off spanning tree on the inter-switch port. What you will get is a spanning tree loop.

What's your objective here?

Bronze

Re: spanning tree

You are right & wrong.

Wrong about BPDUs: Turning off STP will STOP sending BPDUs out but does NOT stop receiving BPDUs.

Check the following link..

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat4224/sw_confg/vvlanref.htm#1006647

Right: Yes, it does not detect the L-2 loops.

Regards...

-Ashok.

With best regards... Ashok ----------- Pls kindly rate if helpful or answered your question.
New Member

Re: spanning tree

so, if i have a switch with spanning tree turned off just on the uplink to the core switch, will the access switch assume it is the root bridge or not ?

Purple

Re: spanning tree

There really shouldn't be a reason you need to shut it off if everything is designed correctly.

New Member

Re: spanning tree

Question remains... What exactly do you want to do that require spanning tree being turned off? If your uplink to core switch is a trunk, DO NOT turn off spanning tree. If it's access switch, and it's the only link out of the access switch, then you can potentially turn off spanning tree (although I strongly advise against it!)

Bronze

Re: spanning tree

It's strongly not advisable to turn off STP as told by others but to answer your question....

Root bridge selection concept is the feature of STP. If you are turning off STP, then the concept of root bridge is not there for this particular switch. Hope it clarifies.

-Ashok.

-Ashok.

With best regards... Ashok ----------- Pls kindly rate if helpful or answered your question.
New Member

Re: spanning tree

so in which case, would each switch think its a root bridge?

Bronze

Re: spanning tree

Reiterating same info, there is no concept of root bridge if you turn off STP.

Assume, you have 10 switches in your network & turned off STP on all switches, then you can remove root bridge concept al together as it's feature of STP.

Regards...

-Ashok.

With best regards... Ashok ----------- Pls kindly rate if helpful or answered your question.
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