[ns] modifications to the ns Mobile IP implementation

[Joerg Widmer <widmer@informatik.uni-mannheim.de>]

Since some of ns' capabilities for wireless simulations were not
sufficient for a past project, I had to make some modifications and
extensions. These as well as some additional tools are now available at
http://www.icsi.berkeley.edu/~widmer/mnav/ns-extension. I believe they
may be of interest to others who run into the same problems with
wireless simulations. Comments and bug reports are of course always
welcome.

Modifications:
- NOAH: a wireless routing agent that (in contrast to DSDV, DSR, ...)
only supports direct communication between base stations and mobile
nodes. This allows for the simulation of scenarios where multi-hop
wireless routing is undesired. Furthermore, NOAH does not send any
routing related packets.
- Improvements to the ns Mobile IP implementation, support for
overlapping service areas of base stations, intelligent selection of
foreign agents, ... 
- Improved handoff mechanism 
- Simple distance propagation model: when parameters for the exact CMU
radio propagation model are not available (send/receive power, ...) the
simple distance propagation model allows to specify the reach of base
stations as a distance (no signal attenuation). When the necessary
information is available, the exact model should always be used instead. 

- Modifications to ad-hockey (the CMU visualization tool), support for
Mobile IP scenarios and some optimizations
- Plotting tool for aggregate node throughput and single flow throughput
- Scenario-generator with simple scenario generation language
facilitating the creation of large scenarios with many base stations

Cheers,
  Joerg

-- 
Joerg Widmer
International Computer Science Institue
Berkeley, CA
widmer@icsi.berkeley.edu