Let me summarize and ask this in a different way - the goal is to provide stability to end-users [service availability (HA)] and it requires cooperation between network service providers [a shorter question with a little spin to make the question fall within the charter of Nanog :-)]...The question is How? When customer in one location is using a multi-homed setup to two providers A and B, with A being the primary (using one of the primary's /24s they've loaned to the customer) and B being the secondary (advertising B with a longer AS_path - simple case that uses default routes). When the customers link to A fails, will the /24 that needs to be globably visible via B (a non-aggregate IP address for B) NOT be globably visible because of the BGP filtering policies of some other provider somewhere, say C ? [I think I know the answer - which is "it will NOT be globally visible, but it depends ... e.g. who A and B is, etc.." but this is not the answer customer's want...They want a viable/reliable solution and I'm not sure how you go about providing it? [if its not possible, I'm stating the obvious, but this is a problem that is only going to get bigger as more /24 types want/require redundant links...i.e. It an operational issue, No?...]... Todd Sandor wrote:
Gee, just when I thought I got the required answers to my "simple" multi-homing questions ....