Stack with difference switch

[Anwar Safian]

Hi expert

I would like to know if we can stack switch between difference model. 

Such as Cat 6500 with 4500, or Cat 9500 with 6500 etc

[Leo Laohoo]

Not even (remotely) possible.

[balaji.bandi]

Short answer  NO, none of them possible.

Instead, you can do Port-channel between those devices (if this is considered as a solution and requirement to extend Layer 2 network, but Control plane will be different in each respective device).

[Giuseppe Larosa]

Hello @Anwar Safian ,

in Cisco world a stack is usually formed by devices that are same model or equivalent.

Your examples are of devices that do not support stack at all like C6500 or C4500 or devices very different.

C6509 with appropriate HW and license can create A VSS pair made of two C6500

The same applies for some models of Cat 4500.

Catalyst 9500 that are newer support stackwise virtual SVL but SVL = VSS. Only a pair of devices in the SVL is supported.

Just to make another example of stackable switches that are not compatible you cannot put in a single stack a C3750X and a C3850 or a Cisco2960 and a C3750.

To be noted Cisco stacks support more then two members but those members have to be of the same family of switches.

Hope to help

Giuseppe

[Anwar Safian]

Hi all

I have one more concern 

1) For same model like Cat 9400, can we stack together but difference slot quantity. Example 4 slot with 7 slot. The line card quantity is same. Example 1 supervisor and 2 line card. 

2) For same model like Cat 9400, can we stack together but each switch has difference supervisor, example Supervisor 1 Module with Supervisor 1XL Module

[Georg Pauwen]

Hello,

1) For same model like Cat 9400, can we stack together but difference slot quantity. Example 4 slot with 7 slot. The line card quantity is same. Example 1 supervisor and 2 line card.

--> Yes. Keep in mind that "Cisco StackWise Virtual is supported only on Cisco Catalyst 9404R and Cisco Catalyst 9407R switches."

2) For same model like Cat 9400, can we stack together but each switch has difference supervisor, example Supervisor 1 Module with Supervisor 1XL Module

--> Yes as well. "Cisco StackWise Virtual is supported on Cisco Catalyst 9400 Series Supervisor 1 Module (C9400-SUP-1) and Cisco Catalyst 9400 Series Supervisor 1XL Module (C9400-SUP-1XL). The feature requires a special, additional, C9400-SUP-UPG-LIC= license with Cisco Catalyst 9400 Series Supervisor 1 Module (C9400-SUP-1)."

You might want to have a look at the prerequisites and restrictions, as there is more to be aware of:

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9400/software/release/16-9/configuration_guide/ha/b_169_ha_9400_cg/configuring_cisco_stackwise_virtual.html#id_75434

[balaji.bandi]

Cat 9400 working different way StackWise Virtual (like VSS)

Make sure they are the same model and modules, best advice make sure you make the SVL with Sup card, both the chassis - make sure sup cards are loaded on the respected slot on both as suggested installation document.

[Giuseppe Larosa]

Hello @Anwar Safian ,

1) different chassis may be used even if it is not considered best practice

2) mixing different types of supervisors can be a challange: they have different TCAM sizes and capabilties so it is a question of implementation in old times C6500 devices I would expect different type of supervisors to be not able to form an SSO pair and the VSS to fail.

I would expect the same here with SVL , but the implementation may have changed .If so in this case I would expect the SUP1 XL to behave like a standard SUP 1 to avoid to overload the peer ( in some specific scenarios).

Hope to help

Giuseppe

[Spooster IT Services]

1. In Cisco for stacking you must have same hardware and same IOS level. So you can not stack different models of Cisco switches.
2. Catalyst switches 6500, 4500 support VSS and 9500 support StackWise Virtual.

VSS: Technology for stacking a pair of switches, which uses conventional 1/10G ports. Used in switches such as Catalyst 6500 and 4500.
Cisco StackWise: Technology for stacking up to nine switches using propietary stacking modules and cables, therefore it is used within a closet. Used in switches such as 3750.
Cisco StackWise Virtual: Very similar to VSS, is like an evolution. Because it also uses conventional 1/10G ports, it can use fiber links and achieve long distances, such as building a switch stack with a pair of chassis geographically distributed. It is also limited to two switches. Used in switches such as Catalyst 9000.

https://www.cisco.com/c/dam/en/us/products/collateral/interfaces-modules/network-modules/white_paper_c11_429338.pdf
https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-9000/nb-06-cat-9k-stack-wp-cte-en.html