Extreme Networks Altitude 3500 Series, Product Reference Manual

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Altitude 3500 Series Access Point Product Reference Guide
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C H A P T E R
9
Configuring Mesh Networking
Mesh Networking Overview
An Altitude 35xx can be configured in two modes to support the new mesh networking functionality.
The access point can be set to a client bridge mode and/or a base bridge mode (which accepts
connections from client bridges). Base bridge and client bridge mode can be used at the same time by
an individual access point to optimally bridge traffic to other members of the mesh network and service
associated MUs.
An access point in client bridge mode scans to locate other access points using the WLAP client's ESSID.
Then it is required to go through the association and authentication process to establish wireless
connections with the located devices. This association process is identical to the access point’s current
MU association process. Once the association and authentication process is complete, the wireless client
adds the connection as a port on its bridge module. This causes the client bridge to begin forwarding
packets to the base bridge node. The base bridge realizes it is talking to a wireless client bridge. It then
adds that connection as a port on its own bridge module. The two bridges at that point are
communicating using the
Spanning Tree Protocol (STP).
Access points configured as both a base and a client bridge function as repeaters to transmit data with
associated MUs in their coverage area (client bridge mode) as well as forward traffic to other access
points in the mesh network (base bridge mode). The number of access points and their intended
function within the mesh network dictate whether they should be configured as base bridges, client
bridges or both (repeaters).
The spanning tree determines the path to the root and detects if the current connection is part of a
network loop with another connection in the system. Each bridge can be configurable so the
administrator can control the spanning tree to define the root bridge and what the forwarding paths are.
Once the spanning tree converges, both access points begin learning which destinations reside on which
side of the network. This allows them to forward traffic intelligently.
After the client bridge establishes at least one wireless connection (if configured to support mobile
users), it begins beaconing and accepting wireless connections. If configured as both a client bridge and
a base bridge, it begins accepting client bridge connections. Therefore, the mesh network could connect
simultaneously to different networks in a manner whereby a network loop is not created and then the
connection is not blocked. Once the client bridge establishes at least one wireless connection, it begins
establishing other wireless connections as it finds them available. Thus, the client bridge is able to
establish simultaneous redundant links.