On 8 Nov 2011, at 21:37, "Leo Bicknell" <bickn...@ufp.org> wrote:
> In a message written on Tue, Nov 08, 2011 at 04:22:48PM -0500, Christopher > Morrow wrote: >> I think actually it wouldn't have caused more validation requests, the >> routers have (in some form of the plan) a cache from their local >> cache, they use this for origin validation... there's not a >> requirement to refresh up the entire chain. (I think). > > I kinda think everyone is wrong here, but Chris is closer to accurate. > :P > > When a router goes boom, the rest of the routers recalculate around > it. Generally speaking all of the routers will have already had a > route with the same origin, and thus have hopefully cached a lookup > of the origin. However, that lookup might have been done > days/weeks/months ago, in a stable network. > > While I'm not familar with the nitty gritty details here, caches > expire for various reasons. The mere act of the route changing > paths, if it moved to a device with a stale cache, would trigger a > new lookup, right? > > Basically I would expect any routing change to generate a set of > new lookups proportial to the cache expiration rules. Which may very well fail because all the routing is hosed. I'm not all that familiar with the potential implementation issues, but I would think that network-local caches would be in order. Even with local caches, I would expect a high incidence of change to trigger something sensible to mitigate this kind of craziness from happening. I am sure enough people have had incorrectly scaled RADIUS farms blow up when a load of DSLAMS vanish and come back again not to repeat such storms. -- Leigh Porter ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
