In message <1gu5sr0.14unfpg1vlsx9bM%manu@netbsd.org>, Emmanuel Dreyfus writes:

>
>What people do with multicast on their own LAN and with TTL = 1 is not
>your business. Please stop whining about it, that's getting rude.  
>

I'd have phrased things differently than Jonathan did, but I'll cite 
what I call "Bellovin's Laws of Networking":

1. Networks interconnect

2. Networks *always* interconnect, even if you don't think they will

3. Networks interconnect at the edges, not the center

What you suggest may work well enough on a LAN.  There's about 20 years 
of TCP/IP history of how things engineered for LANs don't stay there, 
despite all the analyses of the designers.  I hear what you're saying 
and I understand why you're designing it that way -- but it's worth 
thinking about "what if this is more successful than I think?"

		--Prof. Steven M. Bellovin, http://www.cs.columbia.edu/~smb