Split of Cat4500 stack in working network

[Shadow7777777]

Hello

We want to split stack of Cat4500 in to two independent switches without changing access for infrastructure. I was never doing it and not found any info on internet, mostly it is about stacking switches, not spliting. Here is how it looks now:

We have VLAN structure throughout the network managed by Cat4500(layer 3). Cat9200 are layer 2. Some VLANs have IP gateways on Cat 4500 and some on Firewall. 

Services running on switches:

- NTP

- STP

- DHCP

- 802.1x

- routing (OSPF)

How it can be done best?

Which of the services will be affected and which will not be affected by this cluster split? What problems can I encounter? Will the level of redundancy be maintained at the same level?

Many thanks for any hints and advices

[balaji.bandi]

So you mean to say Cat 4500 in VSS you want to make standalone - why you want to do this ?

what is the next plan - connect each other Layer 3 or L3 MEC ? (between Cat 4500)

If the Access switches are Layer 2, then you have spanning loops connecting to 2 different Cat 4500 (have you undertand this ?)

or you would like to convert Layer 3 between Access switch and Cat 4500 ?

[Shadow7777777]

Thank you for your answer, I really appreciate your time and effort. Lets assume luckily no one asked me to do it but I want to know pros and cons of this split in this case and more important, impact on listed running services and redundancy. Going Layer 3 connection between both switches is one of options, is any other?

[balaji.bandi]

When you choosing VSS there is a reason for that  - there are pros and cons (when you design)

Old presentation but help you why VSS ?

https://www.cisco.com/c/dam/global/da_dk/assets/docs/presentations/VSS_0109.pdf

If the Going back to Standalone, that features are opposite of that (most of it)

impact on listed running services and redundancy.

This depends on what Services we are terminating here (if the this only Gateway in Switch - then there are other remedy can be used to fix.

 is any other?

L2 or L3 or VSS between both the chassis, that is only option i think high level.

[Shadow7777777]

If I understand this correctly, STP will be most affected, as during working as VSS, there is no loops. When we separate this stack, STP will detect loops and disable connections which could form loops. We also loose some time and bandwith when some link will go down, so redundancy is worse. What with other services? What will change for them?

impact on listed running services and redundancy.

"This depends on what Services we are terminating here (if the this only Gateway in Switch - then there are other remedy can be used to fix. "

Can you explain what other remedy can be used here to fix? I assume all services should be working if possible, but what will be impact for them when this VSS will be separated?

Many thanks for your explanations, I try to understand this topic in details. We can actually reverse this case, how those services will be impacted if we will merge 2 separate switches in to VSS.