[e2e] Internet "architecture"
Jon Crowcroft
Jon.Crowcroft at cl.cam.ac.uk
Sat Apr 13 12:25:55 PDT 2013
well i've seen scott shenker do his SDN vision talk a couple of times,
and I know nick mckeown's work pretty well, and I do not think they
are bell heads
one point is that computer science has grown up slightly since 40+
years ago, so we are capabile of building way more flexible safe,
secure and performant systems that in the past, when the design
constraints on protocol stacks were set by 1960s ideas of s/w...
so the stuff out of berkeley, stanford, princeton, gatech etc
in this space is not constrained by the old rules
it is deconstrained by new capabilities...
[slightly stolen from John Doyle's cool idea of de-constraining
constraints]
so the realpolitik of openflow is (as it was with GSMP) to get arms
length from the legacy router biz, and move the functionality somwhere
where we can do disruptive innovation
but that is another chapter...
In missive <a062408c2cd8f33d66244@[10.0.1.3]>, John Day typed:
>>Jon.
>>
>>Yes, precisely. The first place it shows up is in ISDN, then Frame
>>Relay, ATM, and MPLS. All those CCITT-like connection oriented
>>solutions. And you undoubtedly are correct, it was brought into the
>>Internet by the Europeans where the new model was largely ignored
>>after the suppression of CYCLADES and the completion other early work
>>such as the Cambridge DS. (As near as I can tell the vast majority
>>of European universities never strayed too far from the traditional
>>ITU model during the 70s to 90s. In fact most of the research still
>>bears a strong mark of it with an Internet veneer.)
>>
>>Yes, it did arrive sometime back and has been a constant source of
>>humor since the ATM lunacy. In fact, this is what makes it so
>>wonderful that OpenFlow and SDN have embraced the ITU world view so
>>completely. The Internet becomes about as anti-Internet as it can
>>get. The Bell-heads have taken over. You have to admit it is pretty
>>amusing.
>>
>>Take care,
>>John
>>
>>
>>At 12:29 PM +0100 4/13/13, Jon Crowcroft wrote:
>>>so the dogma here was that the business of manageing the net was just
>>>another distributed system (see the Cambridge Distributed System)
>>>wherre name services, router services, security services were
>>>implemented in exactly the same way as any other distributred system
>>>(file systems, transaction services, distributed computation tools)...
>>>
>>>but the control plane model of the net arrived in internet-land some
>>>time back - for example simon crosby took ideas (this was around the
>>>time when everyone was trying to do IP over ATM, which morphed into
>>>mpls) from "switchlet" territory with remote computation as
>>>controlplanestechnology...other people, e.g. ipsilon, also took the
>>>seperation of concerns that are
>>>forwarding packets as fast as you can,
>>>from
>>>working out where they should and shouldn't go
>>>and put them on different boxes, originally to be coordinated via the
>>>Generic Switch Management Protocol
>>>later re-discoverd as Software Definted Networkign and Openflow...
>>>
>>>plus ca change...
>>>In missive <a062408a1cd8ddf0a5bcd@[10.0.1.3]>, John Day typed:
>>>
>>> >>The whole distinction of data plane and control plane arises with
>>> >>ISDN. It is a CCITT concept and was never used to describe anything
>>> >>Internet related, either in the US or Europe. Such distinctions only
>>> >>make sense in the beads-on-a-string models of the ITU. Routing,
>>> >>ICMP, DHCP, etc. type functions were characterized as layer
>>> >>management, which can exist to greater or lesser degree in all layers
>>> >>and must be within the layer owing to the different scopes of the
>>> >>layers.
>>> >>
>>> >>Take care,
>>> >>John Day
>>> >>
>>> >>>
>>> >>>the post-hoc rationalisation phrase is way too glib....certainly not
>>> >>>intended to be rude to people that created this cool stuff we all
>>> >>>use - in fact i was conflating three things
>>> >>>
>>> >>>1. a bunch of work fairly recently on optimal protocols and narrow
>>> >>>waist of the hour glass...
>>> >>>2. the ordering of constrints on the design of the internet
>>> >>>protocols (as per dave clarks 88 paper)
>>> >>>and
>>> >>>3. the apparent simplicity of IP - my missing point was that the
>>> >>>complexity pops out somewhere, and that place is in the control
>>> >>>plane....as we've since disovered...
>>> >>>
>>> >>>of course, there were people that ran dynamic distributed routing
>>> >>>for VC networks (X.25 for example - we had switches in the JANET
>>> >>>network that did this) so they were even more complex in both data
>>> >>>and control plane (what with crankback etc etc:)
>>> >>>
>>> >>>so yes, a bit glib really...sorry
>>> >>>
>>> >>>normal service will be resumed as soon as I get my IPTV QoS back :)
>>> >>>
>>> >>>j.
>>> >>>
>>> >>>
>>> >>>On Fri, Apr 12, 2013 at 3:07 PM, Fred Baker (fred)
>>> >>><<mailto:fred at cisco.com>fred at cisco.com> wrote:
>>> >>>
>>> >>>I'd suggest running the assertion by Vint. I made a similar
>>> >>>assertion in a document not too long ago, which I ran by him for
>>> >>>comment, and he told me I was flatly wrong. Yes, the circuit switch
>>> >>>folks were using the term "catenet" to refer to networks that
>>> >>>interoperated through translation, such as frame relay/ATM
>>> >>>interoperation, he asserted, but at least some (he?) was using the
>>> >>>term "Internet" as early as the mid 1970's.
>>> >>>
>>> >>>
>>> >>>On Apr 11, 2013, at 8:59 PM, Dave Crocker
>>> >>><<mailto:dhc2 at dcrocker.net>dhc2 at dcrocker.net> wrote:
>>> >>>
>>> >>>> This is a risky query. There have been previous threads about
>>> >>>>such things as the "start" of the Internet. Instead, I want to ask
>>> >>>>about the "architecture" of the Internet.
>>> >>>>
>>> >>>> Here's a comment that I sent earlier today, to a non-technical
>>> >>>>person who is aware of the overall Internet timeline, but I believe
>>> >>>>does not understand what is distinctive about Internet
>>> >>>>'architecture'. I'm curious about reactions on this list, and any
>>> >>>>possible improvements -- including complete replacement -- but more
>>> >>>>importantly I'm interested in filling in the details:
>>> >>> >
>>> >>>> The original use of the term Internet was to describe a
>>> >>>>distinctive technical design for a distributed, scalable data
>>> >>>>exchange fabric. Its design characteristics differ dramatically
>>> >>>>from those of its predecessor, the Arpanet, and from other related
>>> >>>>efforts.
>>> >>>>
>>> >>>> That's what I sent. To prime the pump for the detail:
>>> >>>>
>>> >>>> By saying 'fabric' I meant to distinguish the mechanism for
>>> >>>>moving raw data from the applications that used it. What I'd class
>>> >>>>as distinctive were the TCP/IP separation, the remarkably modest
>>> >>>>functionality of IP, even to the point of moving it's control plane
>>> >>>>to the next level up with ICMP, and continuing with modest
>>> >>>>expectations the layer below (which made it possible to operate
>>> >>>>over any medium including birds.) This is usually characterized as
>>> >>>>moving robustness to the edges.
>>> >>>>
>>> >>>>
>>> >>>> Thoughts?
>>> >>>>
>>> >>>> d/
>>> >>>>
>>> >>>> --
>>> >>>> Dave Crocker
>>> >>>> Brandenburg InternetWorking
>>> >>>> <http://bbiw.net>bbiw.net
>>> >>
>>> >>--============_-846339397==_ma============
>>> >>Content-Type: text/html; charset="us-ascii"
>>> >>
>>> >><!doctype html public "-//W3C//DTD W3 HTML//EN">
>>> >><html><head><style type="text/css"><!--
>>> >>blockquote, dl, ul, ol, li { padding-top: 0 ; padding-bottom: 0 }
>>> >> --></style><title>Re: [e2e] Internet
>>> >>"architecture"</title></head><body>
>>> >><div>This is a can of worms, but. . .</div>
>>> >><div><br></div>
>>> >><div>At 4:23 PM +0200 4/12/13, Jon Crowcroft wrote:</div>
>>> >><blockquote type="cite" cite>the folks who called it catenet included
>>> >>bob braden who was working at UCL when i was there - of course, we
>>> >>were concatenating networks that ran other protocols (Cambridge Ring,
>>> >>X.25 (transport layer relays) and so on...so perhaps I'm conflating
>>> >>two things - the interconnection of multiple disprate protocol
>>> >>systems, and the IP interconenction of multiple IP networks with
>>> >>disparete layer 2 and below....</blockquote>
>>> >><div><br></div>
>>> >><div>Early on the term catenet was applied without respect to
>>> >>connection or connectionless, but only with respect to forwarding vs.
>>> >>translation (if necessary).</div>
>>> >><div><br></div>
>>> >><blockquote type="cite" cite><br></blockquote>
>>> >><blockquote type="cite" cite>it is the case (as some other folks
>>> >>privately pointed out to me) that IENs (including IEN 1 written at
>>> >>UCL) are Internet Experiment Notes, and go back to mid 1970s, so i'm
>>> >>wrong to say "internet"</blockquote>
>>> >><blockquote type="cite" cite><br></blockquote>
>>> >><blockquote type="cite" cite>however, my point about parsimony is
>>> >>really over compressed - IP trades off simplicity in the data plane,
>>> >>for complexity in the control plane - its not a pure trade off (it can
>>> >>be seen partly as a win-win, as signaling protocols for VC networks
>>> >>can be nearly as complex (or in X.25 and B-ISDN's Q.2931's cases, more
>>> >>complex) as routing protocols....nevertheless, getting routing right
>>> >>and all associated components is seriously non-trivial - other systems
>>> >>(the aforesaid cambridge ring protocol stack) represent a different
>>> >>trade off that is also quite elegant.</blockquote>
>>> >><div><br></div>
>>> >><div>The whole distinction of data plane and control plane arises with
>>> >>ISDN. It is a CCITT concept and was never used to describe anything
>>> >>Internet related, either in the US or Europe. Such distinctions only
>>> >>make sense in the beads-on-a-string models of the ITU. Routing,
>>> >>ICMP, DHCP, etc. type functions were characterized as layer
>>> >>management, which can exist to greater or lesser degree in all layers
>>> >>and must be within the layer owing to the different scopes of the
>>> >>layers.</div>
>>> >><div><br></div>
>>> >><div>Take care,</div>
>>> >><div>John Day</div>
>>> >><div><br></div>
>>> >><blockquote type="cite" cite><br></blockquote>
>>> >><blockquote type="cite" cite>the post-hoc rationalisation phrase is
>>> >>way too glib....certainly not intended to be rude to people that
>>> >>created this cool stuff we all use - in fact i was conflating three
>>> >>things</blockquote>
>>> >><blockquote type="cite" cite><br></blockquote>
>>> >><blockquote type="cite" cite>1. a bunch of work fairly recently on
>>> >>optimal protocols and narrow waist of the hour glass...</blockquote>
>>> >><blockquote type="cite" cite>2. the ordering of constrints on the
>>> >>design of the internet protocols (as per dave clarks 88
>>> >>paper)</blockquote>
>>> >><blockquote type="cite" cite>and</blockquote>
>>> >><blockquote type="cite" cite>3. the apparent simplicity of IP - my
>>> >>missing point was that the complexity pops out somewhere, and that
>>> >>place is in the control plane....as we've since
>>> >>disovered...</blockquote>
>>> >><blockquote type="cite" cite><br></blockquote>
>>> >><blockquote type="cite" cite>of course, there were people that ran
>>> >>dynamic distributed routing for VC networks (X.25 for example - we had
>>> >>switches in the JANET network that did this) so they were even more
>>> >>complex in both data and control plane (what with crankback etc
>>> >>etc:)</blockquote>
>>> >><blockquote type="cite" cite><br></blockquote>
>>> >><blockquote type="cite" cite>so yes, a bit glib
>>> >>really...sorry</blockquote>
>>> >><blockquote type="cite" cite><br></blockquote>
>>> >><blockquote type="cite" cite>normal service will be resumed as soon as
>>> >>I get my IPTV QoS back :)</blockquote>
>>> >><blockquote type="cite" cite><br></blockquote>
>>> >><blockquote type="cite" cite>j.</blockquote>
>>> >><blockquote type="cite" cite><br>
>>> >><br>
>>> >></blockquote>
>>> >><blockquote type="cite" cite>On Fri, Apr 12, 2013 at 3:07 PM, Fred
>>> >>Baker (fred) <<a href="mailto:fred at cisco.com">fred at cisco.com</a>>
>>> >>wrote:<br>
>>> >><blockquote>I'd suggest running the assertion by Vint. I made a
>>> >>similar assertion in a document not too long ago, which I ran by him
>>> >>for comment, and he told me I was flatly wrong. Yes, the circuit
>>> >>switch folks were using the term "catenet" to refer to
>>> >>networks that interoperated through translation, such as frame
>>> >>relay/ATM interoperation, he asserted, but at least some (he?) was
>>> >>using the term "Internet" as early as the mid 1970's.<br>
>>> >></blockquote>
>>> >><blockquote><br>
>>> >>On Apr 11, 2013, at 8:59 PM, Dave Crocker <<a
>>> >>href="mailto:dhc2 at dcrocker.net">dhc2 at dcrocker.net</a>> wrote:<br>
>>> >><br>
>>> >>> This is a risky query. There have been previous threads
>>> >>about such things as the "start" of the Internet.
>>> >> Instead, I want to ask about the "architecture" of the
>>> >>Internet.<br>
>>> >>><br>
>>> >>> Here's a comment that I sent earlier today, to a non-technical
>>> >>person who is aware of the overall Internet timeline, but I believe
>>> >>does not understand what is distinctive about Internet 'architecture'.
>>> >> I'm curious about reactions on this list, and any possible
>>> >>improvements -- including complete replacement -- but more importantly
>>> >>I'm interested in filling in the details:</blockquote>
>>> >><blockquote>><br>
>>> >>> The original use of the term Internet was
>>> >>to describe a distinctive technical design for a distributed, scalable
>>> >>data exchange fabric. Its design characteristics differ
>>> >>dramatically from those of its predecessor, the Arpanet, and from
>>> >>other related efforts.<br>
>>> >>><br>
>>> >>> That's what I sent. To prime the pump for the detail:<br>
>>> >>><br>
>>> >>> By saying 'fabric' I meant to distinguish
>>> >>the mechanism for moving raw data from the applications that used it.
>>> >> What I'd class as distinctive were the TCP/IP separation, the
>>> >>remarkably modest functionality of IP, even to the point of moving
>>> >>it's control plane to the next level up with ICMP, and continuing with
>>> >>modest expectations the layer below (which made it possible to operate
>>> >>over any medium including birds.) This is usually characterized
>>> >>as moving robustness to the edges.<br>
>>> >>><br>
>>> >>><br>
>>> >>> Thoughts?<br>
>>> >>><br>
>>> >>> d/<br>
>>> >>><br>
>>> >>> --<br>
>>> >>> Dave Crocker<br>
>>> >>> Brandenburg InternetWorking<br>
>>> >>> <a href="http://bbiw.net">bbiw.net</a></blockquote>
>>> >></blockquote>
>>> >><div><br></div>
>>> >></body>
>>> >></html>
>>> >>--============_-846339397==_ma============--
>>>
>>> cheers
>>>
>>> jon
>>
cheers
jon
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