On Thu, 02 Sep 2010 15:20:05 +0300 lorddoskias <lorddosk...@gmail.com> wrote:
> I'm just curious - what is the largest OSPF core (in terms of number > of routers) out there? > Presuming OSPF and IS-IS SPF costs are fairly similar, the following page from "The complete IS-IS routing protocol" (really quite a good book, a bit of a shame that there are occasional minor errors that better technical editing would have picked up) shows that relatively modern (although a number of years old now) routers can perform SPF calcs on SPF databases with 10000 routers and 25000 links in less than a second. From that, it would seem that areas / levels are obsolete for most networks for the purposes of reducing SPF calculation time. Still possibly useful for route aggregation, although if BGP is carrying nearly all your routes, that may not be that useful either. http://books.google.com.au/books?id=NxIadsCKZxMC&lpg=PP1&dq="IS-IS"&pg=PA481#v=onepage&q&f=false
