Proxim ORiNOCO AP-4900M User Manual page 11

Introduction
Mesh Networking
are discovered, MAP2 through MAP8 will build a neighbor table from the beacons and probe responses they receive. The
neighbor table contains three kinds of links:
• Active: Link with a Mesh neighbor that has gone through association and authentication, and the port is open.
• Connected: Link with a Mesh neighbor that has gone through association and authentication, but the port is closed.
• Disconnected: Possible link to a Mesh neighbor that has not gone through association and authentication.
From the neighbor table, MAP2 through MAP8 will select the best possible connection to the backbone network. This
connection is the active link. If a link to the backbone on a different channel is significantly better than any on the current
channel, then MAP2 through MAP8 will switch to a new channel and join the Mesh network on that channel.
In Figure 1-2 through
these figures, MAP2 and MAP4 will discover Mesh Portal (MP) 1, and MAP7 and MAP8 will discover MP9. MAP3 is also
within reach of MAP2 and MAP4, but they will not allow MAP3 to connect until they have established a Mesh link to the
Mesh Portal.
Assume that links are established as shown in
Figure 1-3 Mesh Startup Topology Example – Step 2
After the first Mesh links are formed, MAP2,4,7 and 8 will add the Mesh IE to their beacon and respond to probe requests
with a Mesh IE containing the same Mesh SSID and security settings. Eventually MAP 3 will find both MAP2 and 4 and
will setup a Mesh link with the one with the best path to the portal, say MAP2. Optimal paths have low "path costs;" path
costs are calculated based on the number of hops to the portal, RSSI (relative signal strength), and medium occupancy.
Once MAP4 has established a path to the Mesh portal, MAP 3 will also establish a Mesh link with MAP4, but that
connection will remain inactive. It will only be used as a possible alternative uplink for MAP3, and at the same time an
alternative uplink for MAP4. If for some reason the link from MAP4 to MP1 fails, MAP4 can still reach the backbone via
MAP3 and MAP2. The same goes for other MAPs that discover each other.
Figure 1-4, the circles approximately indicate the range of the respective Mesh radios. As shown in
Figure 1-3. Solid lines indicate established links.
AP-4000/4000M/4900M User Guide
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