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Spanning Tree on ERS-5520 switch

Spanning Tree on ERS-5520 switch

Spanning Tree on ERS-5520 switch

I have a question related to STP, if I create a trunk on ports 47,48 over the fiber do I need to disable spanning tree on those ports or it gets disabled right after the trunk is created?

RE: Spanning Tree on ERS-5520 switch

It won't get disabled by default once it's a trunk.  You'd need to disable it manually if necessary.

RE: Spanning Tree on ERS-5520 switch

Thanks biv343,

I though it is recomended to disable the STP on trunk when using VoIP? Please correct me if I'm wrong



RE: Spanning Tree on ERS-5520 switch

I would NOT recommend disabling STP on any edge switch ports. I would recommend using "Fast" learning on any edge switch ports to avoid any possible issues with the delay that Spanning Tree creates between the learning and forwarding states of a port.

 interface FastEthernet 1-46
 spanning-tree learning fast

Have a look at this blog for an example configuration of an ERS 5520 switch and the explanation of each statement;



RE: Spanning Tree on ERS-5520 switch

It's a 'requirement' to disable STP when you have uplink trunks in a SMLT environment.  Outside of that, I typically leave it on all around.

RE: Spanning Tree on ERS-5520 switch

Biv, I had an argument recently with a coworker regarding this, he was insisting on the fact that STP NEEDS to be disbled on ANY kind of trunk, even the single-link ones...

I couldn't find a clear design document that would advocates one way or the other...

RE: Spanning Tree on ERS-5520 switch

As I recall once upon a time Nortel doc recommended having STP enabled on *MLT links, but I believe current best-practice is to disable STP.  As Daddy^3 noted faststart is always the way to go for end-station facing links.

Nortel has a document called the 'Converged Campus Solutions Guide" that you can Google for - its got lots of design guidelines and makes good bed time reading.

RE: Spanning Tree on ERS-5520 switch

Makes EXCELLENT bed time reading.  Put's me to sleep EVERY time.

RE: Spanning Tree on ERS-5520 switch

Thanks guys for all of your help.
Even Nortel TechSupport insists that STP should be enabled on MLT Trunks but Disabled on SMLT and IST.
Referring to those Configuration Guides, they create a lot of confusion some tell you to disable MLT's, where others recommend leaving enabled. I found they have a lot off mistakes, which makes things hard to understand. Especially for guys who just entered the world of VoIP like myself.
I left spanning tree disabled on my uplink ports 47,48

Thanks again

RE: Spanning Tree on ERS-5520 switch

It depends if your network design is sânninge tree based or SMLT based.

When an access switch connects to an SMLT cluster (2 SMLT capable core switches) STP must be disabled on the uplinks to the core.

When an access switch connects to a "normal" core STP must be enabled on the uplinks to the core (and in the core switch(es) also).

On access ports enable STP faststart or (when you are sure you never will have loops in the network) disable STP.

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