All things related to multicast

[Markus Buchhorn <>]

Hi All

We're looking for some enthusiastic (and friendly!) beta testers for 
rcbridge, and hoped we could find some on these lists :-)

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Yet another unicast/multicast bridge? Yes! But why?

rcbridge is an extremely simple bridge between the two worlds. The main 
distinguishing features of rcbridge over other bridges are

 - it has a remote-control interface (hence R.C. bridge)
 - it supports user-controlled stream selection, dynamically.
 - it supports any number (ymmv) of addresses and destinations, dynamically.

The remote control is implemented through a micro-webserver embedded in 
rcbridge. The idea is that the hosting site (with excellent multicast 
connectivity) has to only install the rcbridge and do some minor 
configuration (ACLs, ttl's, port selection, ...) - and nothing else. No more 
configuring group-specific bridges on demand every other day, or forcing 
users into a narrow set of addresses.

When you (the client) point a web browser (or other http client) at the 
rcbridge server, you get allocated your own "tunnel", and you get to 
configure it as you want. You can have multiple tunnels to you if you want.

For rtp-based streams, rcbridge allows you to selectively forward 
any/all/none of them, and change that selection in real time. This is great 
for the bandwidth challenged (as if not having multicast wasn't bad enough!). 
We're using it (or going to be) for AccessGrid session delivery to home, to 
wireless devices, to PDAs/other small-display systems, etc. 

It also automagically forwards rtcp in parallel.

rcbridge 1.0.0 (yes, two zeroes :-) ) is now available for download. You'll 
need Java 1.4 installed on your multicast enabled box.

http://if.anu.edu.au/SW/rcbridge.html

and follow the bouncing ball. 

If you want to have your tunneled multicast traffic delivered to more than 
one machine, have a look at:

http://if.anu.edu.au/SW/rcb-forward.html

which is the associated very simple (command-line, java) client, which allows 
for local remulticasting if needed. You don't need it, to use rcbridge, but 
it might help in your particular situation.

Please try it out and report any bugs/issues to 

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There are many things we still have planned for it, and some things we don't 
like about it yet. The tunneling is a pure payload shuffle, and all that that 
implies. A real tunneling implementation has some benefits (e2e 
transparency), but also some drawbacks (client complexity). We're aiming to 
implement that flexibly. We'll probably move away from Java in 2.x, if Java 
doesn't appeal to you. There's a list of things on the above web page, and 
more in our heads.

We're looking for feedback, bug reports, suggestions, criticisms, etc. We 
want to know how people use it, if/how it helps (or not) and how we can make 
it better. (This also applies to the documentation.)

Cheers,
        Markus

Markus Buchhorn, ANU Internet Futures Project,      | Ph: +61 2 61258810
,
 mail: Bldg #108 - CS&IT |Fax: +61 2 61259805
Australian National University, Canberra 0200, Aust.|Mob: 0417 281429