All things related to multicast

["Curtis, Bruce" <>]

On Feb 24, 2011, at 11:58 AM, Alan Buxey wrote:

> hi,
> 
> unfortunately, many sites just dont 'get' multicast (well,
> logically and physically) . there are a few tools out there
> for checking/testing but i seem to recall that all of the 
> eg beacon software monitors have fallen out of support.

  The dbeacon software may no longer be supported (updated) but it is still 
useful and is still being used (even for IPv6).

http://noctv.funet.fi/



> 
> we entered into a system in which an IPTV system was delivered
> to campus via multicast. really nice - the students could
> watch many channels...and of course, only one stream per
> channel chewed up our WAN link..... not many sites could
> take up such a system so the company changed their client
> to do receive unicast streams instead... (granted, they have
> an adaptive compression system with client feedback loop)
> but now each viewer sucks up the bandwidth. thats just a shame :-(
> 
> maybe the situation will change now that we have these
> new GLOP IP addresses for multicast - it gives sites the chance
> to use an address fairly easily and know that there should
> be no clashes with others.
> 
> as for the tech/takeup... its one of those techs which on the local
> network is often common...on the LAN is not needed (broadcast
> can take over...and sites do directed broadcast to deal with
> leaky needs etc)...and its one of those that is often blamed
> for issues..with a 'just turn it off' mentality - which now seems
> to be targetted just the same at IPv6 :-(
> 
> ..it doesnt help when software vendors dont read the specs and just
> abuse it... i've lost count of the number of packages that
> use a global multicast address...and TTL of 255!! :-(
> 
> alan
> 

---
Bruce Curtis                         

Certified NetAnalyst II                701-231-8527
North Dakota State University