Re: Toward faster international server selection using clever DNS.
On 3/18/2012 9:46 PM, Roedy Green wrote:
On Sat, 17 Mar 2012 09:08:39 -0500, Joshua Cranmer
<Pidgeot18@verizon.invalid> wrote, quoted or indirectly quoted someone
who said :
Note that people already use DNS to point you to the closest physical
servers you have access to, along with load balancing tricks. Basically,
the problem you are trying to solve is already more or less solved.
Oddly though, Google does not do this. I watched it with Wireshark.
So there still might be value is localising Google links in your JSP.
What do you mean by this? If, for example, I do a traceroute to
google.co.at and another to google.com, the route is exactly the same
except for the final server. Judging from whois data, the servers for
both domains are located in Wisconsin, whereas the host computer I
queried from is in Illinois. Given the politics of how ISPs connect to
each other, this is not an unreasonable result (the traffic is forwarded
via what appear to be primarily academic transit links, so I presume
that the amount of money that changes hands for the bandwidth in
question is exactly $0).
Repeating a traceroute from a computer located in another state for the
same domain name produced a different IP address, accessed via a
different set of intermediate hops. I can't map these to physical server
locations, but knowing a little about ISP infrastructures, I suspect
that the server is likely within 20 miles of my location (I happen to be
geographically close to a cluster of major internet exchanges--over half
of the DNS root nameservers have a home in the area).
--
Beware of bugs in the above code; I have only proved it correct, not
tried it. -- Donald E. Knuth