[10428] in North American Network Operators' Group
Re: Topological significance of transport technologies [Was: Re:
daemon@ATHENA.MIT.EDU (Robert Bowman)
Tue Jul 1 20:39:44 1997
From: Robert Bowman <rob@elite.exodus.net>
To: pferguso@cisco.com (Paul Ferguson)
Date: Tue, 1 Jul 1997 17:34:26 -0700 (PDT)
Cc: nanog@merit.edu
In-Reply-To: <3.0.1.32.19970701202028.006a45a4@lint.cisco.com> from "Paul Ferguson" at Jul 1, 97 08:20:28 pm
Agreed.. the distinction between the two layers is becoming somewhat
more and more vague by the day, especially with companies like Ipsilon
and with Cisco's integration of eclipse switching and/or the RSM into
the Catalyst.. how the two layers interact is really the only
importance to the IP packet.
rob
>
> At 05:00 PM 07/01/97 -0700, Robert Bowman wrote:
>
> >layer 2 vs. layer 3
> >
> >tis like comparing a motorcyle to an automobile--both get you places
> >but in fairly different ways
> >
>
> I shouldn't be contributing to this thread, but what the hell.
>
> Its not really Layer 2 vs. Layer 3, its how to integrate the
> two layers and make it work. Mike O'Dell is fond of saying,
> "Pure Layer 3 routed networks are dead," and I can understand
> his point, although I don't necessarily agree with it. I do
> understand, and I think its important for everyone else
> to understand the point here.
>
> Yes, they both get you there, but the pertinent summary to be
> drawn from this comparison is that 'you' are the IP packet,
> and you really don't care what the mode of transport is (e.g.
> frame-relay, leased point-to-point lines, ATM). Each provide
> a pipe. Some have more intrinsic flexibility than others (e.g.
> virtual circuits) and therefore represent a significant reason
> to employ a specific technology over another, given pricing, and
> geographic availability.
>
> Again, IP packets don't really care if it's a motorcycle, an
> airplane, or an automobile (unless its a Harley :-).
>
> It should also be noted that some technologies, such as
> frame-relay are used only in *topologically significant*
> places, ie. customer aggregation, for precisely these
> reasons. In some networks, frame-relay is used for
> customer aggregation, fast-ethernet is used in the PoP,
> and ATM is used in the wide-area (just an example).
>
> - paul
>
