[dns-wg] Question about use of cname in Google's services

Hello everyone Someone asked me question on why google uses cname for their services anyways? I mean I get it that for Google Apps customers it makes sense to have mail.domain.com pointed to a cname rather then A record to a host which may die. But why for their own services? Like e.g "mail.google.com" is cname to googlemail.l.google.com. and googlemail.l.google.com. eventually returns A record. This adds up one extra step in resolution and I wonder why Google does it this way? What advantage they get ? or What advantage they miss if they simply return record which I am getting for googlemail.l.google.com. directly as A record for mail.google.com ? Curious to hear your thoughts. Thanks! -- Anurag Bhatia anuragbhatia.com