In a message written on Thu, Sep 18, 2003 at 10:05:15AM -0400, Todd Vierling wrote:
Anycast is *NOT* a "redundancy and reliability" system when dealing with application-based services like DNS. Rather, anycast is a geographically
I think you'll find most people on the list would disagree with you on this point. Many ISP's run anycast for customer facing DNS servers, and I'll bet if you ask the first reason why isn't because they provide faster service, or distribute load, but because the average customer only wants one or two IP's to put in his DNS config, and gets real annoyed when they don't work. So it is a redundancy and reliability thing, the customer can configure (potentially) one address, and the ISP can have 10 servers for it so if one dies all is well. Is it appropriate for a gTLD? Now that's a whole different can of worms. Personally I think they should return the two anycast addresses, and as many actual server addresses as will fit in the packet. This is the best of both worlds. When it works, geographicly distributed load, redundancy at the IP layer, quick responces. When one of the failure modes is encountered (eg, stuck route) DNS has the information it needs to switch to a backup as well. Redundancy is good. Redundancy at two levels is even better, particularly when they can back each other up. Plus, in this case it costs them nothing, they just have to tweek a config. -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/ Read TMBG List - tmbg-list-request@tmbg.org, www.tmbg.org