Specifications

BPG_11n_v1.0 | Page 15
at every location but configure half of them for different channels -- thus doubling the
available client and/or throughput capacity.
Let’s expand on the latter example further. We now have 4 radios to work with for each area
of the network. Let’s assume that the customer has some mix of 11a, 11b, 11g and 11n
clients. We could configure the radios as follows:
AP1/Radio1: Channel 1 (11b and 11b/g clients only)
AP1/Radio2: Channel 36 (11a clients only; voice handsets perhaps)
AP2/Radio1: Channel 6 – 11 (11n clients only)
AP2/Radio2: Channel 44 – 48 (11n clients only)
Another option would be to create channel layers with load balancing enabled but we need to
be careful here because the typical microcell AP drop layout does not lend itself to an optimal
channel layer load balancing deployment. More about channel layer load balancing later in
this document.
If APs are swapped out one-for-one and APs are placed on the same channel you may need
remove the lower base rates to shrink the interference region. It may also be necessary to
adjust the probe response threshold. Lowering the probe response threshold allows the APs
to ignore probe requests from clients that are farther away or below the threshold.
Please contact Meru Networks customer support for assistance with lowering probe response
thresholds. In the case of a rip and replace (one-to-one or not) plan to do a post deployment
site survey to check for coverage holes and see if we have achieved the goal of 2 to 3 APs
visible at any location throughout the network.
In the event that there is coverage hole, an AP can be placed in that area. It is not required to
adjust other AP locations.
Outdoor
AP300 must be put into NEMA enclosures. Do not use and indoor cable patch (RJ-45 to
RJ-45) outdoors as they will not hold up to the varying weather conditions. Another option is
to keep the AP300 indoor and just mount the antennas outside.
Lightning arrestors are required by code in the US. Lightning arrestors create some level of
loss so you’ll want to compensate for that loss and that of the patch cable when configuring
antenna gain.
The two types of arrestors used most commonly are gas discharged and solid core. The solid
core types appear to have less dB loss and from anecdotal evidence which seem to be
preferred for 11n networks. Both types are consumables and are limited to one time use.
One must pay careful attention to the height that the APs will be mounted as it relates to
antenna selection. For example, if the APs are mounted on a 50’’ pole the default omni
antennas would be a poor choice as the coverage provide at the ground level would poor.
The recommendation for antennas in this case would a directional or an omni with down tilt.
MERU BEST PRACTICES GUIDE | 11n Design, Implementation and Optimization