Specifications

BPG_11n_v1.0 | Page 13
When clients move across a Vcell boundary a hard handoff will occur, similar to a client
moving from AP to AP in a micro cell environment. This handoff will require a re-
authentication and re-association (just as roaming between non virtualized APs would).
This type of handoff is suboptimal and should be avoided if possible.
Inter Vcell roaming can be minimized if care is taken when determining the boundary
locations for give installation. When determining the optimal Vcell boundaries use the
buildings natural attenuation properties to try and isolate one Vcell for the other. For example
if there is a six story building with two controllers, use controller 1 on floors 1, 2 and 3 and
use controller 2 for floors 4, 5 and 6. This way inter Vcell roaming only occurs when clients
roam between floors 3 and 4.
Channel Selection
Again, the recommendation is to use a spectrum analyzer to determine the best channel/s to
deploy. The goal here is to identify sources of non Wi-Fi interference that may be present at
the site/s. One of the most common sources of interference is microwave ovens which
typically have more of a negative impact on 6 through 14 in the 2.4GHz spectrum.
Of course RF environments change so this step of selecting the cleanest channel at the time
of deployment does not guarantee an interference (non Wi-Fi) free channel forever;
nevertheless it is always worth the time and effort to select the cleanest channel from the
start.
Of course with Meru Networks pervasive coverage can be provided by using a single
channel. All of the other channels are available to channel layer where needed to support
high client densities or high throughput applications.
Absent analysis use channel 1 in 2.4GHz and channel 44 – 48 in 5GHz.
Channel 1 is recommended as it will not be as susceptible to microwave ovens. Channel 6 is
not recommended for two reasons: it the default channel for most APs and microwave ovens
can interfere with this channel as well. In the 5GHz range channel 44 – 48 (40MHz) are
recommend as most APs default to channel 36. Keep in mind that some clients do not
support UNI-III (which limits recommendation the UNI-I channels) so verify client support for
the upper channels (i.e. 149 – 165) before deploying UNI-III channels.
AP Connectivity L2/L3
When choosing between L2 or L3 deployment one must consider not only the way the wired
network is (or will be) deployed but also the number of other applications that will be
deployed. E.g., Location Manager, SAM.
Another consideration when determining L2/L3 is which redundancy scheme is used. For
example, with the option 43 redundant controllers and NPlus1 features, L3 connectivity is
required.
The general recommendation is to use L3 connectivity.
MERU BEST PRACTICES GUIDE | 11n Design, Implementation and Optimization