Users Guide

194 | Secure Enterprise Mesh Dell PowerConnect ArubaOS 5.0 | [User Guide
Each ARM-enabled mesh portal monitors defined thresholds for interference, noise, errors, rogue APs and radar
settings, then calculates interference and coverage values and selects the best channel for its radio band(s). The
mesh portal communicates its channel selection to its mesh points via Channel Switch Announcements (CSAs),
and the mesh points will change their channel to match their mesh portal. Although channel settings can still be
defined for a mesh point via that mesh point's 802.11a and 802.11g radio profiles, these settings will be overridden
by any channel changes from the mesh portal.
A mesh point will take the same channel setting as its mesh portal, regardless of its associated clients. If you want
to manually assign channels to mesh portals or mesh points, disable the ARM profile associated with the 802.11a
or 802.11g radio profile by setting the ARM profile’s assignment parameter to disable.
The ARM power adjustment feature does not apply to all ARM-enabled Mesh portals. Indoor mesh portals can
take advantage of this feature to adjust power settings according to their ARM profiles, but outdoor mesh portals
will continue to run at their configured power level to maximize their range. It is also important to note that mesh
points, unlike mesh portals, do not scan channels. This means that once a mesh point has selected a mesh portal
or an upstream mesh point, it will tune to this channel, form the link, and will not scan again unless the mesh link
gets broken. This provides good mesh link stability, but may adversely affect system throughput in networks with
mesh portals and mesh points.
When ARM assigns optimal channels to mesh portals, those portals use different channels, and once the mesh
network has formed and all the mesh points have selected a portal (or upstream mesh point), those mesh points
will not be able to detect other portals on other channels that could offer better throughput. This type of
suboptimal mesh network may form if, for example, two or three mesh points select the same mesh portal after
booting, form the mesh network, and leave a nearby mesh portal without any mesh points. Again, this will not
affect mesh functionality, but may affect total system throughput. For details about associating an ARM profile
with a mesh AP, see “Assigning an ARM Profile” on page 208.
High-Throughput Profiles
Each 802.11a and 802.11g radio profile also references a high-throughput profile that manages an AP or AP
group’s 40Mhz tolerance settings. For information about referencing a high-throughput profile, see “Assigning a
High-throughput Profile” on page 207.
Mesh High-Throughput SSID Profile
High-throughput APs support additional settings not available in legacy APs. A mesh high-throughput SSID
profile can enable or disable high-throughput (802.11n) features and 40 Mhz channel usage, and define values for
aggregated MAC protocol data units (MDPUs) and Modulation and Coding Scheme (MCS) ranges.
Dell provides a “default” version of the mesh high-throughput SSID profile. You can use the “default” version or
create a new instance of a profile which you can then edit as you need. High-throughput Mesh nodes operating in
different cluster profiles can share the same high-throughput SSID radio profile. For information about
configuring mesh high-throughput SSID profiles, see “Mesh High-Throughput SSID Profiles” on page 211.
Wired AP Profile
The wired AP profile controls the configuration of the Ethernet port(s) on your AP. You can use the wired AP
profile to configure Ethernet ports for bridging or secure jack operation using the wired AP profile. For details, see
“Ethernet Ports for Mesh” on page219
Mesh Recovery Profile
In addition to the “default” and user-defined mesh cluster profiles, mesh nodes also have a recovery profile. The
master controller dynamically generates a recovery profile, and each mesh node provisioned by the same master
controller has the same recovery profile. The recovery profile is based on a pre-shared key (PSK), and mesh nodes
use the recovery profile to establish a link to the controller if the mesh link is broken and no other mesh cluster
profiles are available.