Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!cs.utexas.edu!uunet!intercon!amanda@intercon.uu.net
From: amanda@intercon.uu.net (Amanda Walker)
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  Using the 4.2 broadcast addr with 4.3 systems
Message-ID: <1433@intercon.UUCP>
Date: 2 Sep 89 23:01:39 GMT
References: <8909021836.AA24117@ucbvax.Berkeley.EDU> <3842@mentor.cc.purdue.edu>
Sender: news@intercon.UUCP
Reply-To: amanda@intercon.uu.net (Amanda Walker)
Organization: InterCon Systems Corporation
Lines: 23

In article <3842@mentor.cc.purdue.edu>, dls@mentor.cc.purdue.edu (David L
Stevens) writes:
> Multicast, broadcast and host addresses all have an IP network part and if
> it's a collection of hosts (multicast or broadcast), they have to have the
> same IP network part (otherwise you can't route there!).

Actually, from what I understand of the current state of IP multicasting,
IP multicast groups do *not* have an IP network part--they are class D
addresses.  For them to work across gateways, the gateways have to (a)
know about multicast groups and (b) have a protocol by which to communicate
current multicast routing informatin to and from other gateways.

Aside from that, I pretty much agree that "one IP address per interface"
is a reasonable thing to do.  For one thing, it lets subnetting work...

--
Amanda Walker
InterCon Systems Corporation

amanda@intercon.uu.net    |    ...!uunet!intercon!amanda
--
"The trouble with doing something right the first time is that nobody
 appreciates how difficult it was"       --Walt West