RE: Reserved addresses in the SSM range

[Doron Rajwan <Doron@bandwiz.com>]

Hugh LaMaster might be right that the addition of the reserved addresses
mechanism might not worth it. Still, I think that we have (almost) nothing
to loose by reserving addresses. We might gain from being able to tell if a
multicast source is alive, using the "ping" address I suggested.

I do not have a strong opinion on this issue.

Doron.



-----Original Message-----
From: Hugh LaMaster [mailto:lamaster@nren.nasa.gov]
Sent: Tuesday, August 08, 2000 1:12 AM
To: SSM List
Subject: Re: Reserved addresses in the SSM range



On Mon, 7 Aug 2000, Jeremy Hall wrote:

> I am finding it difficult to know why one would wish to reserve addresses.

I agree completely.  I see no reason to reserve *any* SSM groups.

> > First, we have nothing to loose.

Not true.  We have excess documentation.  Look at all the current
IANA multicast address assignments that were made, sit there taking 
up space in the documents, people have to read at various times, 
and 99% of which are never used.

> > Second, we all know that UDP and TCP reserved ports is proven to be
> > helpful.

And harmful.  Look at all the unnecessary port assignments in the
IANA documents.  380K worth of port assignments, almost all of 
which could easily have been assigned dynamically.

> > can think of the following services, each given in a different,
> > predefined,
> > multicast address:

IMHO, static address and port assignments should only be used
for unavoidable bootstrap mechanisms or where a well-known port
is used to support a universal service (e.g. NTP).  All other 
addresses and ports should be dynamically assigned.  If this 
policy were followed, about 99% of these assignments could 
go away.

> > 
> > 1. Time service. The server's local time and time zone every second.
> >    Support packet-loss rate detection.
> >    Support "ping" for multicast.
> >    I suggest address 232.0.0.1 for this one.

OK, I changed my mind.  This is one that should be "reserved"
so that no one will ever use it.


--
 Hugh LaMaster, M/S 233-21,    Email: lamaster@nren.nasa.gov
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