Explanation: Air Monitors (AMs) are Aruba access points (APs) that are configured to operate in a dedicated mode for scanning the RF spectrum and detecting rogue APs, clients, and intrusion attacks. AMs do not serve any wireless clients and can scan all channels in both 2.4 GHz and 5 GHz bands. AMs provide better visibility and coverage of the RF environment than APs that serve clients, as they can scan more frequently and thoroughly. However, AMs also consume more power and network resources than APs, and require additional hardware and licensing costs. Therefore, the optimal number of AMs per floor depends on several factors, such as the size and shape of the floor, the density and distribution of APs and clients, the security and compliance requirements, and the budget and availability of the organization.
According to the Aruba Wireless Intrusion Protection (WIP) Technology Guide1, a general rule of thumb is to deploy one AM for every four to six APs. This ratio can provide adequate coverage and detection for most environments, while balancing the trade-offs between performance and cost. However, this ratio is not fixed and can vary depending on the specific needs and characteristics of each deployment. For example, if the floor has a high density of APs and clients, or a high risk of rogue or malicious activity, more AMs may be needed to provide better security and visibility. Conversely, if the floor has a low density of APs and clients, or a low risk of rogue or malicious activity, fewer AMs may be sufficient to provide adequate security and visibility.
In this case, the floor has 20 APs, which implies a moderate to high density of APs and clients. Assuming that the floor has a rectangular shape and a uniform distribution of APs and clients, a reasonable estimate of the number of AMs per floor would be about 3 to 5, based on the general rule of thumb. This would provide enough coverage and detection for most scenarios, while minimizing the additional costs and resources. However, this estimate may need to be adjusted if the floor has a different shape or a non-uniform distribution of APs and clients, or if the organization has specific security and compliance requirements that demand more or less AMs per floor. References:
- Wireless Intrusion Protection (WIP) Technology Guide
- Installing Air Monitors | Wireless Access - Airheads Community
- Aruba Certified Design Professional Official Certification Study Guide (HPE6-A47)