[REBOL] Re: I think I've figured out IGMP...
From: m:koopmans2:chello:nl at: 23-Aug-2001 6:46
Porter,
Please be aware that a lot of routers don't support multicast. This is what
makes it hard to do that kind of applications. Most streaming media apps use
their own TCP based protocol, I think.
Of course on Intranets you may not have this problem, and REBOLs elegance
always helps!
--Maarten
> OK -
>
> after some experimentation I think I've figured out how to handle
multicasting in REBOL.
>
> -=First instance of REBOL=-
> 1> Open a UDP "listener":
>
> udp: open udp://:9999 ; from the docs
>
> 2> Use set-modes to "join" a multicast group:
>
> set-modes udp [multicast-groups: [[224.0.1.89 your.ip.address.here]]]
>
> 3> Wait for incoming data...
>
> print copy udp
>
> -=Second instance of REBOL=-
> Now - you probably want to send the listener some data...
>
> 1> Open a UDP "sender":
>
> udp: open udp://224.0.1.89:9999
>
> 2> Send some data...
>
> insert udp "test"
>
> At this point, you should see the "test" appear in the first instance of
REBOL. Now - what's really pretty cool about this is that if you have REBOL
running on one or more systems - you can setup 2 or more listeners as
described in the first portion - and data sent by the "sender" in the second
part should reach _all_ of them w/o you having to explicitly address each of
them!!!
> Of course, this isn't exactly new - it's how streaming media multicasts
have worked for the last couple of years, along with Microsoft's own WINS...
But - hey REBOL makes it pretty easy. And here I thought I'd have a major
struggle on my hands. Now to see if I can cobble together a crude
streaming media
server or not with this sort of thing... At least
something like this should make a chat "room" style application easier (if
RIM isn't already using it).
