[ih] The story of BGP?

Louis Mamakos louie at transsys.com
Thu Feb 7 15:20:26 PST 2013

Some other random thoughts..

I think one of the drivers for a replacement for EGP was the arrival of the NSFNET, and the need to support a topology that wasn't the mostly-strict hierarchy that was rooted in the single set of core routers on the ARPANET.  The NSFNET backbone along with the various NSF sponsored regional networks as well as other research networks were quite a challenge to glue together, with somewhat ill-defined borders between networks and IGP domains that spanned multiple networks and their administrators.  A better tool was desperately needed.

This was in addition to EGP-2 suffering under the ever increasing size of the route announcements.  If I recall, there was a lack of incremental updates and EGP-2 relied on IP reassembly of very large fragmented IP datagrams.  A single dropped fragment in practice rendered the entire announcement useless, and I think there were some concerns on how large a package some operating systems were going to be willing to reassemble.  The NSFNET and scores of networks would only add to the pressure of the ever-growing size of the EGP announcements.

Other random thought: CIDR arrived in BGP-4. I remember the transition from BGP-3 to BGP-4 and while strictly speaking not a flag-day, the coexistence of both was intended to be limited because of the difficulty in understanding how classfull and classless announcements would coexist.  I'm not sure what the successor to BGP-4 will be, but it will be called BGP-4 and be backwards compatible and incrementally deployable. :-)  Certainly BGP-4 has been around since the mid-1990's now, right?  It has withstood the onslaught of tremendous improvements since then.

Louis Mamakos

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