Re: Single subnet

Steve Deering <> Sun, 20 May 1990 03:21 UTC

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Date: 19 May 1990 20:02-PDT
From: Steve Deering <>
Subject: Re: Single subnet
To: Vernon Schryver <>
Message-Id: <90/05/19>
In-Reply-To: vjs%rhyolite.wpd's message of Sat, 19 May 90 174142 PDT
Status: O

> From: (Vernon Schryver)
> > From: Steve Deering <>
> > I presume that the FDDI MAC or PHY layer detects unwrap events.  Can they
> > or should they not be signalled upward as "change of topology" events?
> There is nothing in SMT, MAC, PHY, or PMD that reliably and quickly informs
> anything about a distant (ie. at some other station) wrap<->thru transition.

Ah, foolish me to imagine that any useful behavior could be expected
from all that FDDI station management hair.  Forget I even brought it up.

> It is distant topology changes that trash ideas like bridges between
> the primary and secondary rings, or single IP-network for both rings.

The idea of putting single-MAC stations on the secondary ring is what
should be trashed.  (The idea of dual-MAC stations is also regrettable,
in my humble opinion.)

I fear that FDDI will be a case of "too much, too late."

Grumpily yours,