Controllerless Networks

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IAP can support how many unit in a single cluster

Now IAP in a single cluster can support how many unit?

Re: IAP can support how many unit in a single cluster

Please the Aruba Instant VRD for an answer to this question:


Cluster Design
By default, all Aruba IAPs on a Layer 2 domain form a cluster. No hard limit exists on the number of APs or clients that you can support on a single cluster. However, the maximum tested IAP cluster size is 128 IAPs in a cluster.
Guidelines for cluster and mobility design include the following guidelines:

  • Aruba recommends that you use the validated cluster size of 128 APs and 2048 clients per cluster for your cluster design.
  • To allow for some future growth, design a cluster at 80 to 90 % (about 110 APs) of the validated capacity.

Although the validated cluster size limit applies to a cluster, you can expand a deployment to more than 128 APs by deploying multiple clusters that have Layer 3 mobility enabled between them.

  • If a deployment within a contiguous RF domain requires more than 110 APs, divide the deployment into multiple clusters and enable Layer 3 mobility between them.
  • Layer 3 roaming has little to no impact on performance if you enable the Home Agent Load Balancing feature that is part of the Aruba Instant architecture. If you enable this feature, the VC assigns the home AP for roamed clients by using a round robin policy. With this policy, the load for the APs acting as home agents for roamed clients is uniformly distributed across all the IAPs in the cluster.

NOTE: Aruba recommends that you enable the Home Agent Load Balancing feature in deployments in which you expect a high volume of Layer 3 roaming between clusters.


If you need advice, please consult your Aruba Partner or Aruba Sales team. My personal experience is that the better control you have on the wired access switches (and follow the best-practices from the VRD, especially on broadcast control and separation of client traffic) the more APs you can put in one cluster with still proper performance. Starting from about 20-30 APs in a cluster, really make sure you follow the recommendations.

If you have urgent issues, please contact your Aruba partner or Aruba TAC (click for contact details).

Re: IAP can support how many unit in a single cluster

Hi Herman,


I have implemented several cluster of Instant, but they were small and with no special requirements.


1. Do you have experience with clusters of around 100 IAPs? This size of cluster has a good performance or is better two clusters of 50 IAPs?


2. If you have two cluster of Instant and you enable the Home Agent Load Balancing, is the roaming between clusters seamless with no disruption?




Re: IAP can support how many unit in a single cluster

Hi guys,


Anyone with experience with big clusters of IAPs?




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