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How is Formed a Catalyst 3850 Stack

Rosa Ladera
Level 1
Level 1

I am working with 4 C385048U boxes.

version: 16.03.05b

 

Stolz#sh sw stack-ports summary

Sw#/Port# Port Status Neighbor Cable Length Link OK Link Active Sync OK #Changes to LinkOK In Loopback
-------------------------------------------------------------------------------------------------------------------
1/1 OK 4 50cm Yes Yes Yes 1 No
1/2 OK 3 100cm Yes Yes Yes 1 No
2/1 OK 3 50cm Yes Yes Yes 1 No
2/2 OK 4 50cm Yes Yes Yes 1 No
3/1 OK 1 100cm Yes Yes Yes 1 No
3/2 OK 2 50cm Yes Yes Yes 1 No
4/1 OK 2 50cm Yes Yes Yes 1 No
4/2 OK 1 50cm Yes Yes Yes 1 No

 

Stolz#sh sw
Switch/Stack Mac Address : 706b.b920.0480 - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
------------------------------------------------------------
1 Standby c444.a0e8.8f00 1 V06 Ready
2 Member cc5a.53e8.5d80 1 V06 Ready
3 Member cc5a.5365.7a80 1 V06 Ready
*4 Active 706b.b920.0480 1 V06 Ready

 

After each reboot logical sw number is different from fisical sw location.

 

Can someone help to show sw law construction?

 

1 Accepted Solution

Accepted Solutions

Hello
If all hardware,software versions and switch numbers/ priorities are the same then stack election can be dependent on the longest uptime between the members participating in the election and if these are the same then the switch member with the lowest base MAC address will become the master.

Note:
1) switch renumbering depicts the interface numbering of the in the switch stack
2) switch priorities define the preferred role a switch can take within the stack - hugest most preferred

Review here:
https://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/71925-cat3750-create-switch-stks.html


Res
Paul


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

View solution in original post

5 Replies 5

Hello

Switch x priority 15  <   preferred for master switch
Switch x priority 13  <   preferred for standby switch but will become master is master fails
Switch x priority 11  <   preferred for a member switch will become standby if standby fails or become master is both current master and standby fails
Switch x priority 9   <   etc,.....

 

 

res
Paul.


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

What is the relation between logical switch number and phisical switch position in the stack?

 

 

which law regulates the members choice?

Hello
If all hardware,software versions and switch numbers/ priorities are the same then stack election can be dependent on the longest uptime between the members participating in the election and if these are the same then the switch member with the lowest base MAC address will become the master.

Note:
1) switch renumbering depicts the interface numbering of the in the switch stack
2) switch priorities define the preferred role a switch can take within the stack - hugest most preferred

Review here:
https://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/71925-cat3750-create-switch-stks.html


Res
Paul


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

Thanks.

Now I understand.

I have made tests and worked fine.

Finally a have found out that mode button helps to identify the physical position of each switch in the stack.

Hello

Glad to hear that-

Thank you also for the rating

Kind Regards
Paul

Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul
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