On Mon, Aug 18, 2008 at 10:05 PM, Kevin Blackham <blackham@gmail.com> wrote:
Your assumption is generally true with most any provider. They may even accept something smaller, but it won't make it very far if less than /24. It's also a good idea to announce a covering prefix in case some peer network filters on IRR minimums.
The part that Kevin spares you from reading is the "please don't" part. If your goal is to provide HA or DR-like aspects to some $single_application end-site and all you can justify is a one-time allocation of a /24, consider other options. There are already enough /24's in the DFZ both from end-site multihomers and wreckless deaggregation (and those who refuse to build a backbone and/or insist that POP-level convergence towards their network is everyone elses problem, not theirs). Instead of going down this road, I would suggest that you: -call up cisco and purchase a GSS (global dns lb with application availability probes, etc) or -attach your site to a pair of willing upstreams who already have a larger prefix aggregate set aside (say a /18 or something) for end-site multihoming, in which it is expected that the prefix will be originated from disparate AS's (neither of which is the actual end-site). -Tk