[ih] The story of BGP?

Noel Chiappa jnc at mercury.lcs.mit.edu
Thu Feb 7 14:48:46 PST 2013

    > I probably have some old drafts in a large stack of papers upstairs

So, I was unable to resist, and did a quick dip into the piles of paper, and
rescued a few things, which do have the advantage of not fading like my

    > EGP2 (I _think_ that's what we called the version of EGP that was
    > widely deployed

That was indeed the version number of the deployed EGP - see RFC-904. The
name of the proposed follow-on was probably EGP3.

I did find a document from March, 1987, by Mike St. Johns and Jose Rodriguez
entitled "EGP Version 2, Revisions and Extensions to EGP", which says that
"While EGP2 on paper and logically is a new version of EGP, the version
number ... REMAINS the same as in EGP" (i.e. 2). I think we must have decided
that was confusing, because RFC-1093 (which also contains some good history of
the situation prior to BGP) contains a reference to:

  Marianne L. Gardner and Mike Karels, "Exterior Gateway Protocol, Version 3,
  Revisions and Extensions", Working Notes of the IETF WG on EGP, February 1988

which matches my dim memory (that the still-born 'next version' of EGP was
EGP3). I have found other references to EGP3, too, such as the "Status Report
of the Open Routing Working Group" (chair Marianne Lepp), January 1989.

    > I assume it must have loosened the 'no-cycles' restriction

One other problem was that the updates (EGP routing messages were single
packet) were getting too big; the March '87 document describes an incremental
update mechanism.

    > I think what happened next

After looking at a few documents, I think I have a better idea of what

BGP came out in June 1989, but IIRC it was a pretty quick hack; e.g. I
have a document from Guy Almes, March 1989 (i.e. 3 months prior) entitled
"Midterm Inter-AS Routing Architecture" which makes no mention of it. 

I think what happened was that the EGP3 effort (which probably started in
early 1987 or so) quickly metastasized (a most appropriate word) into
something called the Open Routing Working Group, which started down the road
to full-blown policy routing. (See the appendix to RFC-1126, "Goals and
functional requirements for inter-autonomous system routing" for more.) (I
have some minutes/agendas from ORWG meetings in September and November, 1988,
if anyone cares.)

This happened pretty quickly - I have memos written by Ross Callon from
December, 1987 in which the group is moving on from 'an improvement to EGP'
to 'let's do a real policy routing architecture, good for a very large
network'. That eventually resulted in IDPR (RFC-1478, etc) but it took
forever. So in the interim, people went off in a variety of different ways.
One was Yakov:

    > Yakov did an 'improved' BGP for use with the ISO stack, and at some
    > point an upgrade to the IETF BGP basically took that up. 

The original BGP was, as stated, a quick hack because the NSF backbone needed
something better than EGP2.

As part of the inability of the ORWG to get a policy routing design done
quickly that everyone liked, Yakov later did his own policy routing thing,
IDRP (note very slight acronym difference - that was deliberate), which I
think was first an ISO proposal (it does not seem to have ever existed as an
RFC), and was the thing that I remembered as later being taken up into BGP
(not sure if it was BGP-3 or BGP-4 - maybe 4, looking at the references?).

IDRP also got used in a proposal called 'Unified Routing' (see RFC-1322, "A
Unified Approach to Inter-Domain Routing", May 1992).

    > I .. tried to get Proteon .. to lead an effort to do something better -
    > I wanted to do something link-state based - the working name was FGP
    > (in the spirit of the languages, B, C and D...).

I initially tried this (it would have been circa 1987-1988 or so, I remember
a meeting at Proteon with, I think, Hans-Werner Braun) to discuss it.

After that blew up, I wound up doing Nimrod (which was very similar to IDPR,
but was not purely an inter-AS protocol, but a 'top to bottom' routing
architecture). But that's a whole 'nother story...

BTW, there actually was a proposed 'DGP', too - the 'Dissimilar Gateway
Protocol'. None of the three memos I have about it has a date or name, but I
have this dim memory that it was David Mills, and circa 1987.


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