On 25 Jan 2008, at 10:42, Roland Perry wrote:
In article <[EMAIL PROTECTED]>, Matt Palmer <[EMAIL PROTECTED]
> writes
Tunnels all over the place seems like the only way it'd even be
halfway practical. It's more-or-less how phone number portability
works anyway, from what (little) I know.
I don't know about the USA, but in the UK it'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".
Not quite, the simplistic overview is that operators have an
obligation to offer porting wherever practical, so operate ports on a
accept-then-forward principal. If I port my number from CarrierA to
CarrierB, then my calls still pass through A's switch, who transits
the call to B without charging the end user.
For the benefit of completeness, the regulator has mandated that this
situation must change, as CarrierB's inward-port customers are not
protected from the technical or commercial failure of CarrierA. The
industry [www.ukporting.com] has responded and is building a framework
to support all-call-query style lookups to handle number ports.
Best wishes,
Andy
