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Create a loop storm in network "educational Purpose"


Hello I am working on a network with

Ring topology
X440 Switches

And I'm looking for a scenario to get a broadcast storm "loop" for test.

is there any way to do it!?

6 replies

Userlevel 6
Hello Yusuf,

Are you trying to create a loop? If so, plugging them up in a physical loop and plugging in one PC should do the job.
Userlevel 2
Hello Yusuf,

Essentially, all you need to do to initiate a broadcast storm is create more than one layer 2 path between 2 points in your network.

May I ask how you are using this for educational purposes?

Thanks,

Ash
Ash Curtis wrote:

Hello Yusuf,

Essentially, all you need to do to initiate a broadcast storm is create more than one layer 2 path between 2 points in your network.

May I ask how you are using this for educational purposes?

Thanks,

Ash

I am giving a training to client who had a similar problem but with all the configuration in place... after diagnostics we found that in one of the switches on of the ports are not configured probably..
Now we need to get the same scenario in a non-productive environment!
But when I try to "disable stpd s0" on one switch no loops is showing 🙂
Userlevel 6
Hi Yusuf,

I am not sure we have enough information to determine if a loop should happen or not. If you take a port with similar configuration and loop it into another port with the same configuration this should cause a loop as well. STP will not prevent a loop in this scenario unless some type of edge port configuration is used.
Userlevel 6
Remember it takes one broadcast packet to get the loop started so if this a lab of just switches and you create the loop with no clients or ip's on you layer 2 vlans in the mix there is nothing on your layer 2 connections that would create a broadcast packet. you have to prime the pump 🙂
Userlevel 7
EtherMAN wrote:

Remember it takes one broadcast packet to get the loop started so if this a lab of just switches and you create the loop with no clients or ip's on you layer 2 vlans in the mix there is nothing on your layer 2 connections that would create a broadcast packet. you have to prime the pump 🙂

If I remember correctly, most switches drop traffic sourced from itself (at least in EXOS), so you will need more than one switch for this.

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