
What's Anycast and why would I use it? - damianz
http://damianzaremba.co.uk/2013/01/what-is-anycast-and-why-would-i-use-it/
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carterschonwald
I think a neat experiment with the any cast feature of ip6 would be to write a
simple CDN that uses it to provide the locality. Would likely not be a
terribly performant CDN (there's a lot more nifty bits going on with a good
cdn) but it'd probably be a great way to really understand the precise
practical tradeoffs and value of anycast in practice.

IP networks are some of the most complex (and interesting) systems humanity
has ever built, so at some point complex systems need to be experimented with
to see how they'll actually behave!

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jlgaddis
> ... a simple CDN that uses it to provide the locality.

If I'm understanding you correctly, you mean to tell the end user where the
host (being reached via anycast) is physically located?

This exists as part of the AS112 Project[0], assuming server operators have
created/edited the appropriate resource record.

From a machine in my data center (Midwest):

    
    
      $ host -t txt hostname.as112.net prisoner.iana.org | tail -n 2
      hostname.as112.net descriptive text "ICANN DNS Operations"
      hostname.as112.net descriptive text "Culpeper, VA, USA"
    

From a machine in One Wilshire (L.A.):

    
    
      host -t txt hostname.as112.net prisoner.iana.org | tail -n 2
      hostname.as112.net descriptive text "ICANN DNS Operations"
      hostname.as112.net descriptive text "Los Angeles, CA, USA"
    

Those of you in other geographic areas will likely hit other servers.

On a side note, if you manage your own DNS servers, consider adding the
relevant .in-addr.arpa zones to them and help alleviate some of the load. Or,
if you have bandwidth to spare, bring up your own AS112 server. I work for an
ISP and will bringing one on-line in the near future.

[0]: <http://public.as112.net/>

(Note: After lurking for a few years, I finally created an account here so I
apologize if the formatting of this "first comment" is wonky.)

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general_failure
Nice article.

For users of AWS, Route53 supports anycast.
<https://aws.amazon.com/route53/faqs/#Route_53_anycast>

~~~
thirsteh
Same with OpenDNS, Google Public DNS, DNSMadeEasy, etc.

