Intradomain DNS Anycast revisited

Alexander Koch koch at
Sat Mar 26 08:17:06 UTC 2005

On Thu, 24 March 2005 22:25:36 -0800, Bill Woodcock wrote:
> No, because both routers are reached through the same L1/L2 medium, so 
> Quagga can't use link-state to determine reachability of the next-hop.
> You could fix that by getting rid of the switches, and just having a bunch 

Hmh. Thinking of it, for Anycast to work I would rather run
Quagga's BGP daemon and announce the /32 (or whatever it is
in your setup) of the DNS server, and maybe receive a 0/0
from the router (not needed when the router no longer sees
your /32 as then you will simply not receive requests any
longer). All BGP with appropriate timers (some few seconds
only), and if you want you can put some simple scripts on
this box as well that further check if things are working.

All that as less and less real routers[tm] have FE connection
in them where you could work on link-state... and you need a
'dynamic' component to tell you the connection over some GE
aqggregation gear is still there, and if you combine this
with the monitoring of the service itself it should pretty
much work out. Mind you, this is theory. Looks quite sound
to me though.

I like BGP more as I could transport that /32 with no-export
right away.


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