multicast (was Re: Readiness for IPV6)

Thu Jul 11 23:26:58 UTC 2002

Multicast won't become pervasive until there are
applications that use it (as has been pointed out in this
thread), and those applications won't be widely-used until
there is some momentum with high-speed connectivity (ie >
1Mbps and probably more like 10+Mb/s).

Many multicast applications (primarily research/education
networks) are for interactive communication, and useful
interactivity requires lots more bandwidth and much lower
latency and jitter than is available even on cable/DSL.

If you have a chance to see what's going on with multicast
(and anything else) on Internet2, you'll see what happens
when bandwidth and latency become less-significant problems.  
The expansion of Internet2 to diverse disciplines as well as
K-12 and non-research higher-ed schools will expose a larger
and more diverse group to these applications.

Though IPv6 uses multicast more than IPv4, the default use
is basically a replacement for existing broadcast-based
functions (ARP, DHCP, etc). IPv6 will not magically solve
multicast problems outside the local subnet. Multicast being
integrated into IPv6 will probably make it more palatable
than it is now.

Pete.