[ns] Correct use of mac 802.11 in MANET network

[Massimo Reineri]

Hello to everybody!
I would know your opinion about my solution.
I'm working in MANET routing context and I'm simulating a simple network made up
by 4 fixed wireless nodes (A,B,C,D) with mac layer 802_11 (dataRate_ set to 11Mb) 
and a mobile node (E) with mac layer 802_11 but dataRate_ set to 1Mb that moves from the
left side to the right side of the network as shown in the next picture:

| A |             | B |            | C |              | D |

----->>----| E |--->>------------->>-----------------

Now I want to check the data throughput for the communication among node A and node E and viceversa.
The simulator seams to run correctly but I'm not sure that the current implementation
of the mac layer mac-802_11.{h,cc} allows me to deal with this scenario, i.e. it allows me to
use different channel capacities in the same wireless network.
Any help can be very useful and so thank you in advance for your attention!

Best regards,
 Massimo