On Fri, Jan 25, 2008 at 10:42:44AM +0000, Roland Perry <[EMAIL PROTECTED]> wrote a message of 15 lines which said:
> in the UK it [phone number portability] 's done with something > similar to DNS. The telephone system looks up the first N digits of > the number to determine the operator it was first issued to. And > places a query to them. That either causes the call to be accepted > and routed, or they get an answer back saying "sorry, that number > has been ported to operator FOO-TEL, go ask them instead". What happens when a phone number is ported twice, from BAR-TEL to FOO-TEL and then to WAZ-TEL? Does the call follows the list? What if there is a loop? The solution you describe does not look like the DNS to me. A solution more DNS-like would be to have a root (which is not an operator) somewhere and every call triggers a call to the root which then replies, "send to WAS-TEL".