I have an AiroNet mesh of AP1510's deployed outdoors, version 4.1. Backhaul is set on 802.11a radios, and AP access on 802.11b/g. I am trying to play with the backhaul data rate setting and see how if affects various links and mesh stability. The thing I am confused about is whether a per-link backhaul rate can be set or is the rate fixed to a single value for the entire mesh. Cisco documentation claims that it's a single value, which can be set only through the RAP(s), just like the backhaul channel. However, unlike the backhaul channel, it is possible to assign the backhaul rate on MAPs as well (through the web interface as well as CLI). I'm not sure which one applies. A single rate across the whole network doesn't sound reasonable - not all links will be of equal quality in a typical deployment.
Also, the documentation says that 48Mbps and 54Mbps are not supported, but the interfaces allow these rates to be set. How can I be certain of the applicable backhaul rate on a particular link?