Re: Geographic routing hack

["Craig A. Huegen" <chuegen () quadrunner com>]

Note that the particular case in question could also be
an implementation of Cisco's DistributedDirector product,
which responds to DNS requests with the closest server to the
querying machine.

/cah

On Mon, Aug 02, 1999 at 02:59:05PM -0600, Alec H. Peterson wrote:
==>
==>Martin Cooper wrote:
==>> 
==>> Some weeks ago I noticed that 167.216.128.247/32
==>> (www.digisle.net) appears to reach web servers
==>> located in physically different places broadly
==>> dependent on where you see it from.
==>> 
==>> I presume this is done by advertising the same
==>> prefix from border routers which are in seperate
==>> IGP domains or something (confederations maybe?),
==>> but I wonder what people's views on the concept are,
==>> since it could potentially be quite confusing in
==>> certain circumstances (e.g. debugging routing
==>> problems) ?
==>> 
==>> Superficially it seems like a 'cool hack' for
==>> geographic content-distribution (which is what
==>> Digital Island do), but up until now I've always
==>> seen this sort of thing done by exploiting NS
==>> record sorting order properties with the kludge
==>> of different A records in the various zonefiles,
==>> and I wondered if doing it with routing policy in
==>> this way is strictly RFC compliant (or for that
==>> matter if anyone cares if it isn't) ?
==>
==>This certainly isn't a new idea, although it is generally considered poor
==>form to do this with stateful protocols (such as TCP), since the 'closest'
==>instance of the address can change mid-session, and thus cause a reset.
==>
==>Several presentations on using this hack in various situations have been
==>made at NANOG.  See http://www.hilander.com/nanog11 for one such
==>presentation.
==>
==>Alec
==>
==>-- 
==>Alec H. Peterson - ahp () hilander com
==>Staff Scientist
==>CenterGate Research Group - http://www.centergate.com
==>"Technology so advanced, even _we_ don't understand it!"