[dns-operations] Anycast enhancement, was: Re: Is anyone aware of the Community

Joe Abley jabley at ca.afilias.info
Wed Mar 21 21:13:06 UTC 2007

Hi Calvin!

On 21-Mar-2007, at 19:38, Calvin Browne wrote:

> So, here's a suggestion to anycasters - under ipv4, you cast a whole
> class c (I stand under correction here, and guess ipv6 would be even
> more).

The IPv6 authority server anycast platforms that I am aware of tend  
to announce a blocke aligned with the pan-RIR micro-allocation  
policy, on the grounds of critical infrastructure, which means they  
announce a /48.

> would it make sense to use virtual server technology (etc xen) to
> allow separation of services at a virtual server level? or should this
> be left to the application level? my guess is both are applicable.....
> (or maybe this is already being done ;-) ) Scaling issues aside of
> course.

If I understand your question correctly, regardless of whether you  
use virtual servers or discrete physical servers, if you are  
numbering more than one *service* within the same anycast prefix you  
have a shared fate problem. It's not necessarily intractable, but it  
requires some thinking.

This is discussed in RFC 4787 section 4.8.


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