Re: ICMP responses to broadcasts

Jeff Mogul (
23 Apr 1986 1429-PST (Wednesday)

Bob Braden writes:
    [How should IP-level broadcasts be implemented?]: it doesn't
    matter, because IP broadcast is a bad idea in general anyway. We should
    be looking at Deering's proposal in RFC966 for IP multicast.

I agree that multicast is better, in principle. In practice, oodles
of hosts are doing broadcast now, and there is an awful lot of hardware
that supports broadcast but not multicast, or supports multicast
inadequately. So, it really does matter how these broadcasts are done.

Since I wrote RFC919 to propose a standard for broadcasting, I suppose
I should defend it. I asked Jon Postel about this last month, and
he replied:

    Well, "official protocols" (rfc-961) says they are "experimental" and
    "proposed protocols". However, there is no competing proposal. So,
    i'd say to any one that asks, "if you are going to do a broadcast do
    it the rfc-919 and rfc-922 way". I have not received any recent
    questions about it that i recall. Maybe, the next version of official
    protocols should raise the status somewhat.

If anyone would like to propose that IP broadcasting be banned, then
I suspect there will be insurmountable opposition: most people will
keep doing it. Otherwise, let's try to be consistent on how it's done.

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