coprorations using BGP for advertising prefixes in mid-1990s

Jessica Yu jyy_99 at
Fri May 13 21:37:21 UTC 2011

>Does no one remember EGP?

Yes, I remember EGP every well.  When we built the NSFNET T1 backbone in 1987, EGP was the only available routing protocol for exterior routing.  We deployed it and used EGP to exchange routing information with the connected regional networks.  Initially, it worked fine but then when the routing table and traffic grew, we observed that every 3 minutes, the network performance got a hit.  After some investigation, we discovered that it was due to the fact that EGP did routing updates every 3 minutes by flooding the whole routing table to the peer and the process overwhelmed router processor. At that time, the processor on the router did both routing and forwarding.  

Fortunately, Yakov of IBM, Kirk from Cisco and we Merit were working on the development and testing of BGP, which was intended to replace EGP.  BGP does incremental routing updates i.e. it sends its peer the delta whenever routing topology changes rather than flooding its peer with the whole routing table every 3 minutes.  It saved a lot of processing power.  In addition, it reduces routing convergence time since BGP sends its neighbors the updates whenever changes occurs. In the case of EGP, it may take as long as close to 3 minutes after a route change before the routing table got updated.  In addition, BGP has loop detection capability due to its inclusion of AS path information.  These were the technical reasons to replace EGP with BGP at the time.

We worked with regional network reps and started to convert NSFNET to regional peers from EGP to BGP in early 1990s. I also created the BGP Deployment Work Group at IETF to push the deployment of BGP in the whole Internet.



From: Kevin Oberman <oberman at>
To: Dorn Hetzel <dorn at>
Cc: nanog at
Sent: Thursday, May 12, 2011 2:37 PM
Subject: Re: coprorations using BGP for advertising prefixes in mid-1990s 

> Date: Thu, 12 May 2011 17:15:17 -0400
> From: Dorn Hetzel <dorn at>
> >
> >
> > The actual number would be considerably smaller as there were large
> > (for some definition of large) block assignments of ASNs <~1000 or so
> > to various academic networking entities such as NSFNet and regional
> > networks as well as other Federal/Military networking organisations.
> >
> > -dorian
> >
> >
> Well, for one data point, I was issued 3492 around Spring of 1994.

Does no one remember EGP? ASNs are MUCH older than BGP. And we were
using BGPv3 prior to the existence of V4. We used BGPv4 back in the days
when Tony Li would chastise us for reporting a bug in a 10 day old Cisco
build saying that we could not expect BGPv4 code over a week old to
work. He felt that we should deploy new code daily.

The big push was to have v4 available before the old PRDB was frozen by
Merit/NSFnet. (And, who remembers the PRDB?)
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at            Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751

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