Mobility support, Mobile IP and Wireless Channel Support for NS-2

[Charles Perkins <Charles.Perkins@Eng.Sun.COM>]

We announce the initial release of some mobility support for
the NS-2 simulator.  Our code consists of three major parts:

  - A mobility scenario generation subsystem
  - A simplified wireless channel model
  - An implementation of Mobile IP (RFC 2002)

You can download the code from the following URL:
	http://www.svrloc.org/~charliep/mobins2

The mobility generator simulates node movements and provides the
channel model with link up/down information based on the
time-dependent distance between nodes.  The wireless channel
model handles two physical phenomena:

  - Hidden terminal interference
  - Signal capture when there is no interference from hidden terminals

In this channel model, a packet is either delivered correctly,
or not, depending only on the distance between two nodes.
We could call it a "spherical channel" model.  This does not
correspond to any known radio channel, but it is still a very
useful model for beginning to understand routing algorithms
that might be used by mobile wireless nodes.

Our Mobile IP implementation contains the following features:

  - Agent advertisement
  - Registration
  - IP-in-IP encapsulation
  - No security checks; all registrations are accepted
  - No de-registrations; any registration pre-empts earlier ones
  - No agent solicitation

This mobility support package is intended to be very simple 
to use.  Our motivations were to support simulation and
comparison between various ad-hoc networking algorithms,
as well as Mobile IP simulation.

Included in the release are two slide presentations that
exhibit some further discussion of the features available,
and code fragments to illustrate the use of the features.

We understand that there is related work in progress at
CMU, which contains many other useful features, and more
realistic channel models.  We hope to integrate our release
code with their channel models, and possibly use other
features as they become available.

We expect to make improvements to this release in the near
future.  In particular, we expect to release more features
for the Mobile IP simulation, and additional improvements in
the way NS-2 handles the wireless channel internally.  Bug
fixes are welcome, and can be sent to cperkins@eng.sun.com.

Source Code:
        Modifications/additions to ns-2 only(delta)
	-- along with a List of changes

	Complete ns source code (with our additions)


Slide Presentations:
	  - Mobility generator and Mobile IP
	  - Wireless Channel model


						Regards,
						Nirupama Bulusu
						Charles E. Perkins
						Kuang-Yeh Wang