[e2e] Internet "architecture"

Noel Chiappa jnc at mercury.lcs.mit.edu
Fri Apr 12 07:04:23 PDT 2013


    > From: Dave Crocker <dhc2 at dcrocker.net>

    > The original use of the term Internet was to describe a distinctive
    > technical design

Err, that would be '_i_nternet'; that term came first, by quite a few years.
The term '_I_nternet', introduced later, was brought in to denote specifically
to the large one which has nowdays swallowed most (But not all! The term
'airgap' exists for a reason!) of them.


    > for a distributed, scalable data exchange fabric.

I'm not sure how far I'd go with the 'scalable'. The earliest version only
supported 256 networks, and it's been a constant struggle ever since to keep
it growable! (Long diatribe on turns missed elided...)

I think its main novelty, in terms of goals, was its ability to tie together
many heterogeneous kinds of networks; it was that that led to many of its
characteristic architectural aspects (e.g. moving the reliability into the
hosts).

    > What I'd class as distinctive were the TCP/IP separation

True, although i) that wasn't in the earliest versions, and I _think_ (without
checking) that CYCLADES had a similar kind of thing.

    > the remarkably modest functionality of IP, even to the point of moving
    > it's control plane to the next level up with ICMP

Again, I think CYCLADES had that (ditto comment about having to check).

    > and continuing with modest expectations the layer below (which made it
    > possible to operate over any medium including birds.)

I think this (along with the whole 'separate _inter_network header which stays
the same as local headers come and go', with a single internet-wide naming
domain which was used for the names in that header) is probably TCP/IP's big
step over CYCLADES. (And I'd have to check if CYCLADES made an unreliable
packet service available directly to users. If not, add that to the list.)

    > This is usually characterized as moving robustness to the edges.

I think those two are somewhat orthogonal, actually. Yes, to get that 'run
over anything' you probably do have to move the reliability to the edges, but
I can imagine homogeneous networks which also moved reliability to the edges.

	Noel


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