Spanning Tree on Switch 2950

Unanswered Question
Jan 28th, 2008

Dear Cisco Users !

I have a test about Spanning Tree Protocol.On the Switch 2950, I have three ports (1,2,3) in the same vlan( default)

The first connected to the router 1841.

The second connect to Convertor leaded to my NOC

The third used to backup and it connect to modem ADSL .

So I need to configure Fail Over System with STP. But I get the problem. When I unplug cable on the second port, Switch will active the third port , but I can not access Internet, and then I reboot , I can access the internet through the ADSL line.

Please give me some advices,

Thank you so much

I have this problem too.
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Francois Tallet Mon, 01/28/2008 - 13:29

Where is the L2 redundancy in your network? I don't get where STP comes into play. Which port do you see blocked by STP?

Thanks and regards,


dolonghai1986 Tue, 01/29/2008 - 05:30

Dear Francois !

I use the copper line as the redundancy line.You can image like this.



( both lines were connected to the same Switch,not be separated as above, and behind the Switch is the Router 1841)

When the optical copper is broken, the copper line will active(port 3) but I can not access Internet. Please give me some advices,

Thank you so much and best regards

PS: Sorry about my English


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