Minimum VTEP pool in cisco ACI

[kumarH]

Hi All,

Is there any restriction in using /23 or /24 subnet as VTEP pool. I am looking to setup a LAB environment which will not have more than 10 switches per DC.

[RedNectar]

Hi @kumarH ,

Cisco recommends nothing less than a /22

But if it is a lab environment - does it matter what range you use?  You can use anything you want!

Do you know about the 198.18.0.0/15 range, reserved for testing of inter-network communications? It is a great one to use exactly for this kind of case and is often over-looked.  (https://en.wikipedia.org/wiki/Reserved_IP_addresses)

But I doubt anything will break if you use a /24 in your lab.

I hope this helps.

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[Robert Burns]

I'd really advise against using anything less than what's recommended.  Regardless if it's a lab, you'd likely want a "supported" staging area for your prod environment and circumventing what's we've validated isn't a good idea.  I understand you're only looking at a small scale deployment, but is there really an issue allocating a /22?  There's a huge amount of private address space, so it's not like it needs to be publicly routable.   The system divides the global TEP pool into multiple chunks for various DHCP uses such as Node IPs, VPC, KeyChain, etc.  If the system can't allocate these critical resources, you're going to have issues, and the only way to change your TEP pool beyond Day1 is to blow everything away and rebuild.   If you run into any weird issues with this lab and expect TAC support, the first thing they'd do is play the "it's not supported" card.  Make sure you weigh these options.  

Robert