Solved: Re: VLAN Pool limitations

doridor · ‎07-28-2022

Hey, I can't find any information on the capacity of a VLAN Pool with regarding to the amount of encap blocks that can be added to one pool, If any one has any information about this I would love to know

The reason I need to get this number is because I don't wont to allocate any vlan ranges, I want to have the capability to change vlans between domains without any problems, due to the fact I cant have any downtime, I don't want to declare a large pool which i will then need to delete in order to move a Vlan to another pool. I work with automations anyway so managing the pool with single entries wont be an issue.

If any one has any suggestions on how to better handle this issue I would love the hear,
thanks in advance

Claudia de Luna · ‎07-31-2022

I understand exactly why you are asking. In fact I alway recommend this, if feasible, in all my ACI builds. That is, enumerate each vlan in the static pool rather than add via ranges for just exactly the reason you state. So rather than create a static pool with 100 - 105, I will create a pool with 100, 101, 102,103,104, and 105. If, for whatever reason, I need to put Vlan 102 in another domain, no problem. If it was in a range, problem! I recommend this because that has happened to me.

I just did some testing on my simulator and it looks like 4096 is the max as you would expect with12 bits used in 802.1q. You can see the transition from successful posts to failed ones in the log of my script to push 4999 vlans.

====================POST Action: Adding VLANs POST Object: 4094 - 4094
Status Code: 200
Reason: OK
========================================
====================POST Action: Adding VLANs POST Object: 4095 - 4095
Status Code: 200
Reason: OK
========================================
====================POST Action: Adding VLANs POST Object: 4096 - 4096
Status Code: 400
Reason: Bad Request
	 Error Text: unknown property value uni/infra/vlanns-[GDL-Legacy-POOL]-static/from-[vlan-4096]-to-[vlan-4096], name dn, class fvnsEncapBlk [(Dn0)] Dn0=, 
========================================
====================POST Action: Adding VLANs POST Object: 4097 - 4097
Status Code: 400
Reason: Bad Request
	 Error Text: unknown property value uni/infra/vlanns-[GDL-Legacy-POOL]-static/from-[vlan-4097]-to-[vlan-4097], name dn, class fvnsEncapBlk [(Dn0)] Dn0=,

This makes sense (to me)...regardless of our ability to put a range in, under the hood the fabric will need to enumerate. Strictly speaking we should not be able to go higher than 4095 and my test in the simulator shows that we are not unnecessarily limited by the interface. At the end of the day, this is what I would expect for any network device, ACI fabric or otherwise.

If you look at the Scalability guide @Gilad Meirovich provided, while its not specifically stated, I'd focus on the Fabric Topology > Configurable Options table and see if you are going to hit any of those limits.

Not an authoritative answer I know, more of a practical one, but I hope it helps.

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