Wired Intelligent Edge

Hi There,

 

For a project we are using CX6300 switches that are VSF stacked and obviously i want to avoid a split brain situation. The vsf best practices for cx 6300 suggests connecting the two Mgt ports with a cable or a common layer two domain.

 

Its simple with two switches, just connect the Mgt ports with an ethernet cable and job done.

 

But how to deal with 2+ switches in a stack? I do not have a separate out-of-band management network. What would be the best practise in this situation?? Any suggestions...

 

Cheers

Setting up a dedicated and eventually isolated (but it's not essential) network for every VFS Members' OoBM ports should be easy if you have a simple 8 ports (or more) Layer 2 switch...isn't it? it's nothing fancy or expensive (as example I use a 24 ports Aruba 2530 as collector of some OoBM ports).

Thanks for your suggestion, this would be my preferred option too. However for this large deployment the additional hardware for the oobm switches are not included in the design and has to be added as an after thought.

 

How about if i used the vsf-stack itself for a split brain detection through a VLAN? Something like this;

 

 

Maybe I'm wrong...but such design reminds me something recursive like the famous hammer nailing itself (Malcolm Fowler):

 

 

Greetings!

 

A bit of clarification on split-brain behavior for VSF on AOS-CX:

 

Only the primary (member 1) and user-defined secondary are capable of operating as a VSF Conductor (formerly referred to as master). As such, a split brain scenario will only occur if these two switches end up on opposite sides of the split. If a split occurs and both the primary and secondary are on the same side of the split, all members in the other fragment will go down and stay down until the connection to the primary is restored.

 

For this reason, only the primary and secondary members require their management ports to be connected for VSF split detection to function properly.

Thanks for explaining the behaviour of split-brain.

 

Obviously i am aware that a dedicated out of band network is the preferred way to go but i am exploring alternative options that could provide all of part of the split-brain functionality.

very nice explanation 
suggestion to Aruba - this should be more clear on new VSF config guide re CX ..

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Marvin Spiteri
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Original Message:
Sent: Aug 26, 2020 02:36 PM
From: Matthew Fern
Subject: VSF split brain detection with 2+ switches

Greetings!

 

A bit of clarification on split-brain behavior for VSF on AOS-CX:

 

Only the primary (member 1) and user-defined secondary are capable of operating as a VSF Conductor (formerly referred to as master). As such, a split brain scenario will only occur if these two switches end up on opposite sides of the split. If a split occurs and both the primary and secondary are on the same side of the split, all members in the other fragment will go down and stay down until the connection to the primary is restored.

 

For this reason, only the primary and secondary members require their management ports to be connected for VSF split detection to function properly.