Connecting multiple switches together

[BroganOs]

I usually connect my switches with at least 2 cables aggregated together for redundancy, they end up in a sort of daisy chain.

 

But this weekend one of the switches bricked severing the connection between two buildings.

 

I have two switches in each building and could in theory have one or more cables from each switch going to the opposite switch in the opposite building. Creating better redundancy. But will that create some sort of loop. Or does anyone have any recommendations for me?

[geohanson]

We use stacking switches to solve this.

You can then create an LACP trunk between SW1 and SW2 in the stack, and these are then linked to a similar stacked pair of switches in each building.

 

Same applies with servers - LACP trunk with 2x10GB connections, one to SW1 and one to SW2. Because the switches are stacking you can create the LACP bond across the two switches.

 

You can then theoretically lose one stacking switch from each building and the network will still function.

 

If your switches don’t support stacking, I think you can work it with Spanning Tree and redundant links, where one link will be used until STP detects it is broken and then it moves over to the other link. I don’t know the ins and outs of how it works but it is possible with STP.

 

Hope that’s useful!

[Norphy]

That’s not stacking, that’s creating a link aggregation group.

 

Stacking switches is where you manage multiple switches from a single management interface. This means that how ever many switches that the model supports in a stack can need managed from a single IP address, rather than multiple ones.

 

That said, in essence what you’ve said is correct. To connect switches together with multiple uplinks the switches need to be managed switches which support some kind of link aggregation technology. LACP is a commonly used one which is supported by all of the major switch vendors.

[geohanson]

That’s not stacking, that’s creating a link aggregation group.

 

Stacking switches is where you manage multiple switches from a single management interface. This means that how ever many switches that the model supports in a stack can need managed from a single IP address, rather than multiple ones.

 

That said, in essence what you’ve said is correct. To connect switches together with multiple uplinks the switches need to be managed switches which support some kind of link aggregation technology. LACP is a commonly used one which is supported by all of the major switch vendors.

 

Sorry didn’t explain it very well.

You need the stacking switches in order to create the redundancy that is needed and allow one of the switches to fail without the network going down. You can create LAGs between single switches in each building but it doesn’t get around the issue of a switch failure. For this you need ‘proper’ stacking switches.

Some switches are stackable in that they can be managed from a single IP address but not all switches will allow you to create LAGs across multiple switches.

 

Using STP will allow you to do this if you don’t have stacking switches but I’ve never done it that way before so can’t be much help with that.

[BroganOs]

If I understand your both essentially suggesting that I’d be link aggregating over two switches? (I know I’ve probably over simplified it a lot)

[BroganOs]

Having don’t a bit of research, my edgeswitches don’t allow stacking or lcap. But it’s good to know what’s possible. Thanks for the advise.

[powdarrmonkey]

Create a ring, or multiple rings, and prevent loops with a (properly configured) spanning tree.

[Davit2005]

Spanning tree is the way to go if you cannot go for stacked switches.

 

To be honest I'd always setup spanning tree if my switches allowed.

Edited February 17, 2020 by Davit2005

[BroganOs]

Thanks guys [emoji1303]