From: John Conzone (jkconzone@xxxxxxxx)
Date: Sat May 13 2000 - 14:47:10 GMT-3
Brian, the OSPF hellos are local, though. They won't proceed off the
local net because of the TTL of 1, correct?
What I am hearing is that beyond the local, or directly connected
network, multicasts will not be passed, or "routed" bewteen interfaces,
without multicast routing turned on. Thats fine. Thats what I've been trying
to find out. I may have THOUGHT it worked, but it probably didn't if what
you're saying is correct.
Thanks!
----- Original Message -----
From: "Brian Hescock" <bhescock@cisco.com>
To: "John Conzone" <jkconzone@home.com>
Cc: "ccielab" <ccielab@groupstudy.com>
Sent: Saturday, May 13, 2000 10:23 AM
Subject: Re: mulicast question again
> John,
> What specific application(s) are you referring to? Yes, multicast is
> used on routers when you don't have muliticast routing enabled, such as
> eigrp using 224.0.0.10, ospf using 224.0.0.5 and 224.0.0.6 etc. But to
> the extent you seem to indicate, I believe the answer would is no. Perhaps
> there's a redundant path where multicast routing is enabled or they're
> using the "ip multicast help-map" command to convert a broadcast into
> multicast at the far end. Let me know which application you're referring
> to and the multicast group and I can check. Thanks,
>
> Brian
>
> On Fri, 12 May 2000, John Conzone wrote:
>
> > I have another question regarding multicast, and I can't seem to
find the answer. Here goes.
> > A standard cisco router with no multicast routing enabled. He gets a
packet destined for a mulitcast group.
> > What does he do with it. Does he drop it? Does he send it to his default
gateway since he has no path to that address? I know what he does with a
unicast, and I know what he does with a broadcast, both with a helper and
without.
> > All the literature dicusses the various means of routing multicasts,
and using CGMP to control it at the switch layer, and I'm okay with all of
that. But as I have stated before, I have worked on lots of lans that don't
have IP multicast turned on, yet use multicast applications. How does
multicasting work in a routed/switched lan with no bells and whistles (ie.
no PIM or IGMP snooping or CGMP). I just can't seem to find any
documentation on that.
> > Specifically I think about "ghosting" pc's on a lan.
> > Thanks all!
> >
>
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