Switch Stack Addressing

[Slayton]

I am still new to Meraki so I have a very basic question.

When stacking C9300 switches, do you go into the local status page and assign IP address info and then the entire stack uses that same IP address, or do you need to assign a different IP address to each switch in the stack?

I did see this so I am thinking they do not.

When using static IP addressing for switch management interfaces rather than DHCP, the management IP address cannot be individually altered for each stack member through the dashboard. Once the stack is configured, all members will display the management IP address of the active (primary/master) switch, where the control plane resides. It is important to note that if a change to the management IP is made after the stack has been configured, that change will apply to the active switch and will be reflected across all stack members. The management IP is shared and not unique to each switch within the stack.

Note: Due to the management IP behavior described above, accessing the Local Status Page from any member will direct to the local status page of the active switch, regardless of which stack member you are physically connected to.

[Mloraditch · Accepted solution]

In IOS-XE based switch stacks, the entire stack shares an IP. There is no need to use the local status page to assign an ip unless you have no dhcp available for setup regardless it would not be on an individual basis.

[Slayton]

I felt I knew the answer but wanted verification so thank you for that.

I can setup DHCP but we use MAC reservation on anything we do DHCP. So if I were to go that route, I could pick any switch in the stack (say switch #1) and reserve an IP based upon that switch MAC correct ? Then when the active switch is finalized (could be any switch in the stack), it would receive the same IP address because of the control plane of the stack.

[Mloraditch]

I'm actually unsure of that and tend to think that wouldn't work because that macs aren't shared. It's also possible the stack master could change if there was ever an issue. I guess if you don't allow any ips to be handed out without reservation and can't have even a temporary open pool you would need to use the local status page

[Slayton]

I feel the few  minutes it takes to access the local page and set the static IP address is warranted. I tend to connect stack switches individually to allow them to load the correct firmware, then complete the stack and fire it up. Then go in and do the switch configurations via the portal.

[compunetJimmy]

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@Slayton wrote:

I felt I knew the answer but wanted verification so thank you for that.

I can setup DHCP but we use MAC reservation on anything we do DHCP. So if I were to go that route, I could pick any switch in the stack (say switch #1) and reserve an IP based upon that switch MAC correct ? Then when the active switch is finalized (could be any switch in the stack), it would receive the same IP address because of the control plane of the stack.

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Negative. In my experience, the MAC address used for DHCP by the master switch isn't associated with the switch MAC address. We've had to resort to just determining what the MAC address is for a lease and creating a reservation after that. 

Lots of room for improvement still with Meraki-managed Catalyst switching. 

[Slayton]

Interesting and thanks for your input on this. I will just stick to static IP via local status page since all of our equipment comes here to the DC first.

[compunetJimmy]

Just be aware there's a difference between the CS and IOS-XE Native versions of the firmware with how static addressing is handled.

Starting with 17.15 firmware, all statically assigned addresses are done with the Layer 3 interfaces modules. I say this because I was going to statically assign address to my Catalyst stacks in Meraki, but then found out you're enabling L3 routing, and I don't want my switches to be able to perform routing for connected clients. 

I'm waiting for VRF support coming later and hoping* this might bring some kind of management VRF support. 

https://documentation.meraki.com/MS/Cloud-Native_IOS_XE/Cloud-Native_IOS_XE_Overview#Changes_in_Beha...

[compunetJimmy]

Here's some documentation I encourage you to read that's fairly helpful.

- Stacking Catalyst Switches:
https://documentation.meraki.com/MS/Stacking/Switch_Stacks#auto-stack+note:~:text=added%20for%20redu...

- Catalyst Installation Guide:
https://documentation.meraki.com/MS/MS_Installation_Guides/Catalyst_9300-M_Series_Installation_Guide

[Slayton]

I have read those already. I try to always search for the answer first and then if it isn't 100% clear, I'll ask others what they do in that situation.