how to manually assign master role to a summit stack ?

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I'm new to summitStack configuration, my question about manually assign the master role, is because I need to connect the fiber uplink to the Active Core (our configuration is two Cores, Active-pasive) and the redundant link to the backup, or what do you recommend?
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Karina Del Moral

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Posted 3 years ago

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Patrick Voss, Alum

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Hi Karina,

The stack acts as one logical unit so it does not matter which slot is the master. Are these links going to be a lag to the core? Can you provide a description of how you would like to connect them?
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Karina Del Moral

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Hi Patrick,

I previously configure and connect a two switch stack, so no problem there, using the sfp ports One switch has the uplink to the active core, and the other one the backup.

Now, I'm configuring a 4 Summit X440-48t stack (to replace an old users Blackdiamond) and was wondering if the Master should have the active uplink and the backup the other one.... that's why my question about manually assign the  role..
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Patrick Voss, Alum

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If you build the switch manually (IE not use easy stacking) you can set the priority for each node like so:

configure stacking slot <SLOT#> priority <1-100>

Keep in mind that if for some reason slot 1 reboots and slot 2 takes over as the master that it will not give the master status back to slot 1 when it comes back.

Ultimately it does not matter what slot you plug the up-link into considering it is acting as 1 logical switch. If you are looking for redundancy just in case a slot fails I would recommend building a LAG where one cable is plugged into slot 1 and the other is plugged into slot 2. Both these ports act as one logical unit and they kind of "share" the traffic as well but if slot 1 fails the cable plugged into slot 2 will take over all the traffic.

Hope this helps!
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Karina Del Moral

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Patrick, one more question, for the LAG port configuration, doesn't matter if the links are one Active core and the other to the standby? Can this configuration "confuse" the Core ESRP and make them failover? :s
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Patrick Voss, Alum

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I apologize, I think i misunderstood your setup. In order for ESRP to work properly in a active/standby situation the device needs a path to both of them. This way if the active core fails the standby core can take over.

The scenario I provided only works for connecting from one logical device to another. Example, a stack that consist of four switches to a stack that consist of two switches. Even though the connections are spanning across slots in the stack it is still one logical connection using two physical connections.

If you want to add the ESRP redundancy into it then you can setup two LAGs where one goes to the active core and one goes to the standby core. This would consist of two logical connections that consist of four physical connections.

So to answer your question you cant split a lag to two different logical devices. There are scenarios where you can do this setup but it would require a protocol like MLAG.

I hope this explains everything.
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Karina Del Moral

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Thanks again,  Now I understand it.... better :)
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Karina Del Moral

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Thanks Patrick!!