Greg Foletta - Bits and Blobs
Much has been written and a lot of analysis performed on the global BGP table over the years, a significant portion by the inimitable Geoff Huston. However this often focuses on is long term trends, like the growth of the routing table or the adoption of IPv6 , dealing with time frames of of months or years.
I was more interested in what was happening in the short term: what does it look like on the front line for those poor routers connected to the churning, foamy chaos of the interenet, trying their best to adhere to Postel’s Law? What we’ll look at in this article is “a day in the life of the global BGP table”, exploring the intra-day shenanigans with an eye to finding some of the ridiculous things that go on out.
As you’ll see, we end up with more questions than answers, but I think that’s the hallmark of good exploratory work. Let’s dive in.
The first step, as always, is to get some data to work with. Parsing the debug outputs from various routers seemed like a recipe for disaster, so instead I did a little yak-shaving. I went back to a half-finished project BGP daemon I’d started writing years ago and got it into a working state. The result is bgpsee, a multi-threaded BGP peering tool for the CLI. Once peered with another router, all the BGP messages - OPENs, KEEPALIVES, and most importantly UPDATEs - are parsed and output as JSON.
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