Bill, wo...@pch.net (Bill Woodcock) wrote:
> > 2. We plan to use this anycasting based setup for DNS during initial few > > months. Assuming low traffic for DNS say ~10Mbps on average (on 100Mbps > > port) and transit from just single network (datacenter itself) - is this > > setup OK for simple software based BGP like Quagga or Bird? > > Yes, and in fact, that's how nearly all large production anycast networks are > built??? Each anycast instance contains its own BGP speaker, which announces > its service prefix to adjacent BGP-speaking routers, whether those be your > own, or your transit-provider's. Doing exactly as you describe is, in fact, > best-practice. Well, let's say, using Quagga/BIRD might not really be best practice for everybody... (e.g., *we* are using Cisco equipment for this) Using anycasting for DNS is, to my knowledge, best practice nowadays. > > 3. IPv6! - Is /32 is standard? We have only one /32 > > allocation from ARIN and thus if using /32 seems like hard deal - we have > > to likely get another /32 just for anycasting? or we can use /48 without > > issues? Also, is /48 a good number for breaking /32 so that we can do /48 > > announcements from different datacenters in simple uni casting setup? > > A /48 is quite reasonable. Announcing a whole /32 just for your anycast > service would be wasteful. Why? It's simply another prefix, no matter how big. It might look wasteful, but if *that* is the allocation you *have*, it's the one you ought to use. One should be careful - people do filter on allocation lengths, so breaking out a /48 out of a /32 allocation and advertising it on its own can lead to it being filtered. Elmar.
