Re: Cluster Addressing and CIDR

"Rokitansky, Carl-Herbert" <> Tue, 14 January 2003 16:46 UTC

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Date: Tue, 14 Jan 2003 01:21:56 +0100
To: "J. Noel Chiappa" <>, "Bob Braden" <braden@ISI.EDU>, "Vaudreuil, Greg M (Greg)" <>, <>, <>, <>, <>, "Elisabeth Porteneuve" <>, <>, "Vittorio Bertola" <>, <>, "Joey Borda **star*walker**" <>, <>, <>, <>, <>, <>, <>, <>, <>, <>, <>, <>, <>, <>, <>, <>, <>, <>, "Ron Sherwood" <>, "Stephen Waters" <>, "Stephane Bortzmeyer" <>, "Simon Higgs" <>, <>, "Richard J. Sexton" <>, <>, <>, "Jkhan" <>, "Ben Edelman" <>, "@quasar Internet Solutions, Inc." <>
From: "Rokitansky, Carl-Herbert" <>
Subject: Re: Cluster Addressing and CIDR
Cc: <>, "Richard Henderson" <>, <>, <>, <>, "Bruce Young" <>, "Alexander Svensson" <>, "Joe Baptista" <>, "David Goldstein" <>, <>, <>, <>, "Joop Teernstra" <>, <>, <>, <>, <>, <>, <>
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Dear Noel,
Dear Bob,
Dear Greg,

As you might understand, I am quite happy to hear from you all, and of 
course memories pop up on the work of the IETF / PDN Group in which the 
"Cluster Addressing Scheme" was discussed intensively. In fact, the main 
idea was to extend the "Subnet Addressing Scheme" but in the "other 
direction", with the intention, that not only subnets, but even several 
different Internet networks appear to be reachable "locally" e.g. by direct 
X.25 links, so that similar routing decision algorithms can be be applied, 
using an appropriate "Cluster Addressing Mask", in which only those bits of 
the IP address corresponding to the same "cluster" are set to "1".

In fact, the "Cluster Addressing Scheme" was never published as RFC or IEN, 
but was published in:
[1] Carl-Herbert Rokitansky, "Internet Cluster Addressing Scheme and its 
Application to Public Data  Networks",  Proc.  9th International Conference 
on Computer Communication  (ICCC' 88), pp. 482-491, Tel Aviv, Israel, 
Oct./Nov. 1988.

[2] Carl-Herbert Rokitansky, "Hierarchical VAN-gateway 
Algorithms  and  PDN-Cluster  Addressing Scheme for Worldwide 
Interoperation between Local TCP/IP Networks via X.25 Networks", Informatik 
Fachberichte 205, Springer Verlag Berlin, pp. 758 - 774, Feb. 1989.

and as IETF/PDN Drafts:
- Carl-Herbert Rokitansky, "Internet Cluster Addressing Scheme", PDN Draft 
for Internet Engineering Task Force (IETF), July 1989.

- Carl-Herbert Rokitansky, "Application of the Cluster Addressing Scheme to 
X.25 Public Data Networks and Worldwide Internet Reachability Information 
Exchange", PDN Draft for Internet Engineering Task Force (IETF), July 1989.

It's "only" a bit more than 13 years ago, but it seems to be an eternity, 
taking into account, what happened since then !

Bob Braden wrote:
 >It's never too late to repent! The RFC Editor would be glad to
 >publish your latest Internet-Draft, even at this late date. We
 >think it is important that seminal ideas be reflected in an
 >archival document series.
 >Bob Braden

Of course, I would support, if the RFC Editor would be interested to 
publish the latest internet draft of the "Cluster Addressing Scheme", etc., 
in an archival document series, but I have to check, if I have an 
electronic (and readable) copy available myself, so I would appreciate if 
some appropriate people could also check if they have an easier access to 
such copies in an electronic archive !

So, please expect subsequent message(s) on this issue.
If you need any additional information, please let me know !

Thanks for bringing this issue up,
Best regards,

Carl-Herbert Rokitansky (Roki)

PS: As far as I can recall (having currently no access to any old 
documents) the IETF (or plans for it ?) was established in 1984 in a 
meeting in Malvern, UK at RSRE, in Sept (?) 1984 (could anyone please 
confirm), in which several of us participated ! Do you have any plans 
already to celebrate the 20th anniversary of the establishment of the IETF 
! Please keep me informed. Thanks ! Roki.

Am 10:48 13.01.03 -0500 schrieben Sie:
>I was reading a paper by Paul Francis and Ramakrishna Gummadi, and a
>reference caused me to re-read an interesting-sounding old paper they
>referenced (RFC-1380, "IESG Deliberations on Routing and Addressing") to
>refresh my memory of it, and further to read similar documents it referenced
>(e.g. RFC-1287, "Towards the Future Internet Architecture").
>In so doing, I was upset to see that the references included no mention of
>the work of Carl-Herbert Rokitansky, whose "cluster addressing" scheme was
>the first case I can recall of someone proposing to group a number of IP
>network numbers together, and treat them as a single entity - the idea which
>later became the key concept behind CIDR.
>Granted, the original cluster addressing scheme had a different goal entirely
>(it had to do with getting routing to work correctly with multiple X.25
>networks) - but still, it put the thought of that mechanism in the heads of
>everyone who was around at the time.
>So, if anyone writes about CIDR in the future, can they please include a
>reference to the cluster addressing work? Thanks.
>         Noel


H.-Prof. Dr. Carl-Herbert Rokitansky

Universit├Ąt Salzburg
Inst. f. Computerwissenschaften
(Computer Science Institute)
Jakob-Haringerstr. 2
A-5020 Salzburg, Austria

Tel.: +49-172-241 04 71 (GSM)
Fax: +49-172-50-241 04 71 or +43-662-8044-611 or +43-662-64 69 90 18
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