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New Member

Simulating UniDirectional Link Failure

Hi folks,

I may be losing the plot but can I simulate unidrectional link failures using fibre to help my CCNP studies? I thought it would be a simple matter of pulling out just the rx on one of my switches but that brings the int down. Is this how it's supposed to work?

I want to do this to look further into udld.

thanks

Dave

3 REPLIES
Cisco Employee

Re: Simulating UniDirectional Link Failure

You can use PACL to simulate unidirectional link failure. UDLD uses 0100.0ccc.cccc as destination MAC address.

So configure a PACL denying this mac address and apply the same to the interface on which you need to simulate the link failure.

HTH,

Nagendra

New Member

Re: Simulating UniDirectional Link Failure

Thanks Nagendra,

I'll look up PACL.

Now what about the fibre failure I simulated, is expecting that to be a unidirectional link failure a wrong assumption?

ta

Dave

New Member

Re: Simulating UniDirectional Link Failure

It is my understanding that your assumption is right. One thing to note is that both switches will have to establish a bidirectional state once before UDLD will shutdown an interface. Try connecting them and do a "show udld neighbors"

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