.ORG problems this evening

Thu Sep 18 17:01:18 UTC 2003

On Thu, 18 Sep 2003, E.B. Dreger wrote:

: TV> Anycasting only works as a redundancy scheme when you have a
: TV> mesh of *partially* overlapping BGP advertisements, so that a
: TV> client has a guarantee that at least one address in the mix
: TV> is located elsewhere from the rest.
:
: Don't be silly.  This is like claiming that multihoming only
: works if you spread services over different netblocks.

We're talking about application (DNS) redundancy here, not transport-level
(6to4 anycast RFC comes to mind) redundancy.  With this in mind:

: Ergo, that's why one withdraws the routes when a pod dies.
: Routes need to reflect what's up.

BGP doesn't know when a DNS server dies.  Therein lies the findamental
problem of using anycast as an application redundancy scheme.

-- 
-- Todd Vierling <tv at duh.org> <tv at pobox.com>