Split the Core switch (c9500) stack into two separate Core switches.

[Shehri]

Hi all,

I need some help to understand the stepwise approach to split my existing core switch stack of 2 x c9500 into separate core switches(like Core1 & Core 2). Will appreciate your help.

Switch Model : c9500-12Q

SW : CAT9K_IOSXE

Regards,

Shehri

[balaji.bandi]

The changing topology will need to change other design considerations. (especially the devices connected to existing Core, what mode they are connected, will be changed)

if they are StackWise virtual, then you need to remove StackWise virtual config (this will have downtime)

Disabling Cisco StackWise Virtual

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/16-9/configuration_guide/ha/b_169_ha_9500_cg/configuring_cisco_stackwise_virtual.html#concept_ad5_4wx_31b

Next step if you like to have CORE1 and CORE2, then you need to decide what approach you like to connect each other ?

Using Port-channel, or Layer 3 Link?

how is your access or distribution switch connection dual home ? Layer 2 and you like to change Layer 3.

You will see different model, Google - Campus LAN and Wireless LAN Solution Design Guide

[Shehri]

Hi

There are two modules in stack and all the downstream switches or devices are connected in redundancy. Core switch in stack is anyways connected to two different providers. So splitting them won’t get any outage during the implementation.

Secondly, these will have layer 3 connectivity.

I have done this in other catalyst switches but never on 9500 series so wanted to cross check if there is any difference in terms of command or order of operations.

Design perspective, we just have to make these as two cores connected.

Kindly let me know what are the steps or things I should be consider for this change. Thanks

[balaji.bandi]

I follow below steps :

1. Break the SVL ( or turn off Secondary switch)  (remove all connected cables from secondary)

2. connect console erase the config.

3. Configure as Layer3 as per the design

4. connect all the cables back, and test is that work as expected.

5. Once you confirmed all working, 

6. take out primary SVL switch offline do the same, and connect back Core to Core and apply layer3 config ( also any OSPF config and test it)

hope this helps your high level.

since you got a chance to build, try to upgrade the latest stable IOS XE code.