Flapping links in STP

[bvarga]

Hi,

permanent topology change caused by a flapping link can degrade network performance in a switched network. How can I protect my STP against the flapping link?

best regards

VBala'zs

[rsissons]

You can minimise the effect of spanning tree by manually designating the root of the spanning tree as one of yout hub switches but, really, the only solution is to address the physical problem as to why the link is flapping.

[bvarga]

Hi,

I have found some indirect information that Cisco switches change a link to error-disable state if the link is flapping, but no information how it is working.

See the command reference of 3550:

- "errdisable detect cause"

- "errdisable recovery"

http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12114ea1/3550cr/cli1.htm#1964832

The config guide do not include any information about this feature. :-(

Do You know how it is working and whether it is a standard based feature?

best regards

VBala'zs