AMX NXA-WAPZD1000, Operation/Reference Manual, Page: 142 / 154

Smart Mesh Networking Best Practices
138 NXA-WAPZD1000 ZoneDirector Smart WLAN Controller
Smart Mesh Networking Best Practices
Choosing the Right AP Model for Your Mesh Network
The NXA-WAPZD1000 supports both 802.11g and the newer, faster 802.11n APs with which to form a mesh
network. Because mesh throughput degrades with the number of hops, the best performance can be achieved
using the newer, faster 802.11n APs. However, 802.11g APs will also form a suitable mesh network if your
client devices do not support the newer 11n standard.
The most important point to note, however, is that the two technologies cannot be mixed in a mesh topology.
All nodes in a mesh must be 802.11n or 802.11g. You cannot mix 802.11n with 802.11g APs in a mesh.
Additionally, dual band 11n APs can only mesh with other dual band 11n APs, and single band 11n APs can
only mesh with other single band 11n APs.
In summary, build your mesh network as follows:

Ensure that all APs are dual band 802.11n

Ensure that all APs are single band 802.11n

Ensure that all APs are 802.11g
Calculating the Number of APs Required
This is an important step in planning your mesh network. In this step, you will calculate the number of total
APs (Root APs and Mesh APs) that are needed to provide adequate coverage and performance for a given
property. If you plan to support Internet grade connections for casual web browsing, plan for a design that
delivers 1Mbps of throughput in the entire coverage area. For enterprise-grade connections, plan for 10Mbps
of throughput.
WiFi is a shared medium, of course, so this aggregate bandwidth will be shared amongst the concurrent users
at any given time. In other words, if the network is designed to support 10Mbps, it would support 1 user at
10Mbps, or 10 users at 1Mbps each. In reality, due to statistical multiplexing (just like the phone system - the
fact that not all users are using the network concurrently), if you use an oversubscription ratio of 4:1, such a
network could actually support 40 users at 1Mbps.
But first, some background on mesh technology, and its impact on performance. A Root AP (RAP) in a mesh
network has all its wireless bandwidth available for downlink, because the uplink is wired. For mesh APs
(MAPs), the available wireless bandwidth has to be shared between the uplink and the downlink. This
degrades performance of a mesh AP as compared to a Root. With this background in mind, a two-step process
to calculate the number of APs will be used.
Step 1
In step 1, we assume that all APs are Roots (i.e. have an Ethernet drop available), even if this is actually not the
case. This is our most optimistic number - when all APs are connected by wire. The best way to do this is to
use the handy calculator provided on the Big Dogs Partner Portal at
http://partners.ruckuswireless.com/sales_tools/quoting_guide
A sampling of results generated by the calculator, for an environment with 25% Line of Sight/ Cubicle, 50%
dry wall and wood, and 25% concrete and tile, is shown below. This table is useful for some quick calculations
on number of APs. However, it is recommended that you use the calculator on the Big Dogs Portal, so that
your exact RF parameters and square feet can be entered for your particular site.
The above restrictions apply only to AP-to-AP communication as part of a mesh, not
to AP-to-client communication. For example, 802.11g clients can connect to an
802.11n mesh, and vice versa.
Note that eMAP APs are treated as Root APs for the purpose of calculating coverage
requirements. Although an eMAP is actually a a subset of Mesh AP, because the
calculator does not distinguish between Root APs and eMAPs, for this calculation,
you should treat them as Root APs.