On Wed, Oct 29, 2008 at 10:40:37AM +0400, Marco Hogewoning <marcoh@marcoh.net> wrote a message of 23 lines which said:
isn't the whole idea of anycast that you create redundancy by adding more machines/locations in the same address space ?
Having one anycast cloud does provide redundancy and then protection against *some* problems, typically physical problems (power failures, fire) or dDOS.
So what exactly are you trying to gain by adding multiple anycast blocks, that's not exactly clear with me.
But anycast by itself does not protect you against problems with BGP/routing. If Pakistan Telecom announces one of your prefixes, or if a wrong/outdated bogon filter blocks it, anycast by itself won't help. Here, a second anycast cloud with a second prefix may help.