Hi, On Fri, 21 Apr 2006, Ruchti, Marcus wrote:
I don't think flapping routes will increase due to the assignments of PI space, as in the most cases ISP's are requesting those for customers and offers managed multihoming solutions. So announcing these routes into BGP is the responsibility of an ISP.
First off: there has been some discussion whether 200K routes is a problem or not. If the numbers stayed at that level (how can we ensure that?), that wouldn't be a huge problem. Bigger one is dynamicity. Huston's study indicated that there are folks whose BGP announcements flap (due to TE) intentionally 1000's of times a day. Multiply that by the number of sites (and add sBGP or friends to the stew) and you may start thinking that your DFZ router might have better things to do than process that cruft. And now responding to your specific comment, I do not agree with "So announcing these routes into BGP is the responsibility of an ISP." -- the _sites_ decide how they want to advertise; the biggest decision of the ISP is whether it does BGP flap damping for these or not. Virtually all multihomers use their own AS number -- agree? If you agree, I guess what you're saying is that in most cases the ISPs set up the AS numbers and the multihoming at customer's equipment, customer's premises or colo, customer's AS number, etc.? Indeed, I believe in significant number of cases, a consultant (whether from one of the ISPs or an outsider -- I'd personally prefer an outsider as (s)he wouldn't have a conflict of interest) sets up the multihoming setup. But that doesn't preclude said consultants, other consultants, or local network engineering staff from adjusting the set-up later on. If one of the ISPs had sole management of the setup, that would seem somewhat at odds with the provider independence principle. -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings