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Cisco 3850 Stack Reelection Question

Hi All,

Just need some clarification on the stack reelection on Cisco 3850 Switch

let say I have 4 switches in a stack ring.

Switch 1(active) - Priority 15

Switch 2(standby) - Priority 14

Switch 3(member) - Priority 13

Switch 4 (member) - Priority 12

The switch priority are 15,14,13, and 12 respectively. Based on their priority, If switch 1 failed, switch 2 will become active, switch 3 will be the standby and switch 4 will stay as member. And if switch 1 went back online, switch 1 will not be preempted, and my question is after the reelection process. Will the stack election, elect switch 1 as member or standby?

From cisco document, it states that "The factors for electing or reelecting a new standby switch are same as those for the active switch election or reelection, and are applied to all participating switches except the active switch."

From my understanding on this, based on the above scenario, the old active switch after it went online or a new added switch in the stack will participate in the election along with the standby and member switches only in the stack ring.

Thank you in advanced.

Cisco Employee

Switch 1 will join as member

Switch 1 will join as member because stack master n standby already exists. 

Please note that priority comes into the picture during election. But if your stack already has a master/member then no further election is gonna happen when switch 1 will come back online.

However if switch 3 (current standby) goes down after switch 1 comes back online then switch 1 will be chosen over switch 4 (due to higher priority) for new standby election. 

Frequent Contributor

Re: Switch 1 will join as member

Hi guys,

After some 1/2h reading through the 3850 stack threads I have this question:
- I have this 3 SWs stack

rswcore#show switch
Switch/Stack Mac Address : 544a.00e7.xxxx - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
1 Standby 3820.5692.xxxx 1 V05 Ready
*2 Active 544a.00e7.xxxx 15 V03 Ready
3 Member a0f8.4958.xxxx 1 V07 Ready

I want/need standby role to come to switch no3. Here're the steps I am thinking to do
a) switch 3 priority 14
b) reload slot 1

Should I expect any business impact except switch 1 ports related connections?

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