there have been public demonstrations of released routers supporting upwards of 1.5M IPv4+IPv6 prefixes and demonstrations on routing churn convergence time. <http://www.lightreading.com/ document.asp?doc_id=63606> contains one such public test.
The http://www.lightreading.com/document.asp? site=testing&doc_id=63606&page_number=6 part may be a bit misleading. For me it would be more interesting to see what happens when 500k routes completely disappear from the router then come back. I want to see a 500k route push from a neighboring CRS in that amount of time... Of course the routes can switch quick when you use a layer of indirection (folks have been doing that for a few years now). My question is how fast can you install routes from a standing start (or a 1/4 of a standing start if this is 2M prefixes). I will leave the question on whether it is actually worth an investment in time and resources as an exercise for the reader <grin>. Lightreading people, test it like that! It will be much more entertaining and perhaps even a bit enlightening to see how major vendors compare on "brand new" route installation into RIB and FIB. They only have to twiddle a couple bits to make indirection work quickly. Having to deal with a brand new prefix is a completely different problem.