Replacing ACI Leaf Switches with Different HW Model

[Mohamed_Saad]

I was wondering if it is possible to replace the ACI leaf with a different model, I'm very familiar with actual procedure on how to replace a Leaf switch but my question is if I have two Leafs "Nexus 93180YC-FX" want to replace them with two new Leafs for what ever reason "more throughput or EoS/EoL etc" can I get two new Leafs Nexus 93180YC-FX3 or Nexus 93240YC-FX2 then replace the current Nexus 93180YC-FX one by one?

Leaf 101 and 103 are in a vPC pair and all servers are dual connected to both of them in a vPC

Leaf 101 "Nexus 93180YC-FX" --> Replace it with Nexus 93240YC-FX2

Then

Leaf 103 "Nexus 93180YC-FX" --> Replace it with Nexus 93240YC-FX2

So is that a supported scenario and what happens during the transition period when I have Leaf 101 as Nexus 93240YC-FX2 and Leaf 103 as Nexus 93180YC-FX

Any problems? 

[Robert Burns · Accepted solution]

No issues swapping Switches in a VPC pair from the same generation.  Just be mindful of the Interface IDs - try to use the same ones as previously so all your Interface policies fall back into place.  

Robert

[Mohamed_Saad]

Thanks @Robert Burns  for sure that makes sense to have the same interface IDs as most likely it is 1:1 

When you say same generation that means FX goes with FX .. EX goes with EX etc so it does not matter if FX goes to FX2, Correct?

[Robert Burns · Accepted solution]

It's not as intuitive as that.  1st Gen switches (in which we leverage merchant silicon (Broadcom)) aren't compatible with Gen 2 and later switches (which we replaced merchant silicon with our own custom ASICs).  

1st Gen - those switches which are already EoL and lacking an EX,  FX, or GX designation.   2nd Gen+ is everything from EX onward (EX, FX, FX2, GX, GX2 etc.).  

While it's supported to mix Gen2+ together, (Ex. FX with FX2) in the same VPC domain, I would try to limit/avoid it if possible for anything other than a HW migration activity like you're planning.  Reason is that there are some features/capabilities which are platform specific (MacSec, PoE, TCAM size etc).  Ideally, VPC peer switches they should have the same capabilities. 

You'll find this documented in the L2 Config Guide: https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/2-x/L2_config/b_Cisco_APIC_Layer_2_Configuration_Guide/b_Cisco_APIC_Layer_2_Configuration_Guide_chapter_0100.html

Robert