SNR Smoothing
One of the challenges in WLAN routing is the ephemeral nature of RF, which must be considered when
analyzing an optimal path and deciding when a change in path is required. The SNR on a given RF link can
change substantially from moment to moment, and changing route paths based on these fluctuations results
in an unstable network, with severely degraded performance. To effectively capture the underlying SNR but
remove moment-to-moment fluctuations, a smoothing function is applied that provides an adjusted SNR.
In evaluating potential neighbors against the current parent, the parent is given 20 percent of bonus-ease on
top of the parent's calculated ease, to reduce the ping-pong effect between parents. A potential parent must
be significantly better for a child to make a switch. Parent switching is transparent to CAPWAP and other
higher-layer functions.
Loop Prevention
To ensure that routing loops are not created, AWPP discards any route that contains its own MAC address.
That is, routing information apart from hop information contains the MAC address of each hop to the RAP;
therefore, a mesh access point can easily detect and discard routes that loop.
Cisco Mesh Access Points, Design and Deployment Guide, Release 7.3
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Mesh Network Components
Adaptive Wireless Path Protocol