All things related to multicast

[Marshall Eubanks <>]

Sure;

   The genesis of this was the VirginJamCast multicast button (actually
a windows only downloadable 
executable). I mentioned the existence of this at the mboned meeting at
the 49th IETF, and
everyone seemed to think that this would be a good thing. People felt
that way internally here too,
so we made it. The only real hassle was the certificates required.

   It uses native java code running in the browser virtual machine. It
tries to 
join a group (the version on our website tries to join one of ours, but
this is easy to
change and any group with > 1 packet per second would do). If after a
brief wait period
it receives packets, connectivity is known; if not, it assumes there is no
connectivity. This result is used to direct the user to one of two web
pages - connected
or not connected. These can, of course, say anything you want in html.

  Our experience is that if you are going to get multicast traffic from
a group, you
start getting it pretty fast. Obviously, our approach lends itself to
false negatives (if
there is no group data when you try it, due to congestion, say), and
does not address
partial connectivity (for certain ASs, but not others, say). What we
were aiming for was
something simple enough that you could tell a naive user to do it over
the phone
and get a meaningful result.

   We used java running in the vm so that the button ran totally on the
user's machine,
but without requiring a download (and for some platform independence).

   There is no direct reporting of results back to a central site. (Of
course, whoever
maintains the web servers will know which IP addresses accessed the button.)

Marty may want to add something as he did the code.

                                    Marshall

Tony Rimovsky wrote:
> 
> Marshall, can you send a description of how this applet operates and what
> criteria it uses to determine multicast connectivity?
> 
> thanks
> /tsr
> 
> At 04:06 PM 2/13/2001, Marshall Eubanks wrote:
> >Hello, all;
> >
> >Well, we finally got the multicast button to work !
> >Authored by Marty Schoch, this browser applet is intended to make it easy 
> >for
> >users to test their multicast connectivity.
> >
> >The button is GPL Java code, although I am not sure if there is
> >a CVS yet.
> >
> >                                          Marshall Eubanks
> >---------------------------------------------------------------------------------------------------
> >Relayed from Marty Schoch :
> >
> >I'd like to announce the Multicast Tester, an easy way
> >to find out if YOU are multicast enabled.  Simply point
> >your browser to
> >
> >http://www.multicasttech.com/mt
> >
> >and follow the directions.
> >
> >We're testing/fixing the applet now, so please
> >feel free to send feedback.
> >
> >NOTE: currently this does NOT work on the Mac
> >
> >
> >--
> >Marty Schoch
> ><>
> >Join the I-Force
> >Download the MCT Player
> >http://www.on-the-i.com

-- 


                                   Regards
                                   Marshall Eubanks

   Multicast Technologies, Inc.
   10301 Democracy Lane, Suite 201
   Fairfax, Virginia 22030
   Phone : 703-293-9624          Fax     : 703-293-9609     
   e-mail : 

     http://www.on-the-i.com