OVERVIEW
--------

MHealth is a cross-platform, graphical, interactive multicast monitoring tool. 
MHealth provides a graphical tree representation of a multicast session 
displaying all of the hops from source to receivers with packet loss 
statistics. MHealth also provides logging facilities for both the routes and
the RTCP (Real Time Control Protocol) packets.

REQUIREMENTS
------------

MHealth requires the freely available mtrace tool and the binaries for the Java 
virtual machine v1.1.6 or higher. The README.INSTALL provides information on 
where to find these tools and how to make them available for MHealth.  
This pre-release has only been tested on Sun Solaris and SGI Irix, but the 
platform-independent nature of Java should make portability trivial (at least 
to UNIX-based systems).  Future versions of MHealth will not require the 
mtrace binary and be fully portable.

Logging the trace data and/or the RTCP packet data can take up a sizable amount 
of disk space depending on the size and duration of the session. Logging a
active session for an entire day can take between 5 and 10 megabytes of 
disk space.


STARTING MHEALTH
-----------------

MHealth is invoked as follows:

   	mhealth [SessionAddr/Port]


RUNNING MHEALTH
----------------

When MHealth is started, you will be presented with menu options.
There you can verify or set the session address and port, turn 
logging of the routes (mtraces) and RTCP packets on or off, and
set the directory for the logs.

Once you hit "Apply" from the Menu screen, MHealth will immediately
start listening for RTCP packets. As soon as the source has been
identified, it will be displayed as a box at the top left of the
window. As soon as receivers are identified, they will be placed
along the bottom of the screen. The color of the receivers will be
green for 0% to 1% loss, yellow for 2% to 9% loss, red for 10% or greater
loss, and pink if they did not report loss.

Once an mtrace of a receiver is completed successfully, the receiver
box will be removed from the bottom of the window and drawn as the leaf
of a tree with the source as the root. Routers are shown in white if
they are reporting low loss or not reporting, yellow for 2% to 9% loss,
and red for 10% or greater loss.

You can click on any node for a pulldown menu of additional options.
You can view stats on any node. For nodes in the tree, you can choose 
to prune or expand them to customize your view. For receivers, you can
choose to mtrace them next, meaning after whatever current mtrace is
running finishes, that node will be the next to be traced.

LOGGING
-------
The log files ROUTE.LOG for the mtraces and RTCP.LOG for the RTCP packet
information. If a file by that name already exists in the specified 
directory, MHealth will append to it. 

The RTCP packet log has the following format for each line: timestamp,
IP address, ssrc id, and report count. If the report count is greater
than one, then there are report count iterations of the fraction lost
and jitter values from those reports.

The timestamps used are from the Java Date class, which is the number
of seconds since January 1, 1970, 00:00:00 GMT. A conversion script
called ts is included in this distribution, which takes the timestamp
value as a command-line parameter and outputs the text date:
	% ts 909520261844
	Timestamp is Tue Oct 27 12:31:01 PST 1998

BUG REPORTS
-----------

We have a list of issues and enhancements in the README.ISSUES file
included with this distribution. Any additional suggestions, problems, 
or bug reports can be sent to davidm@cs.ucsb.edu or almeroth@cs.ucsb.edu.

Thanks!