Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucsd!ames!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!gryphon!vector!telecom-gateway From: covert@covert.enet.dec.com (John R. Covert 08-Sep-1989 2121) Newsgroups: comp.dcom.telecom Subject: UK->USA, which carrier? Message-ID: Date: 9 Sep 89 01:26:50 GMT Sender: news@vector.Dallas.TX.US Lines: 32 Approved: telecom-request@vector.dallas.tx.us X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@vector.dallas.tx.us X-TELECOM-Digest: volume 9, issue 360, message 4 of 7 John Pettitt asks: >On another subject, does anybody know how the choice of LD carrier for >the US domestic part of international call is made ? BT have been >known to use both MCI and AT&T (I have had error recordings from both). >Do they use an others ? Is it some clever least cost system or is it >just a % split. I suspect that it's not least cost as I have had both >carriers on calls from London to Mountain View CA. The carrier for the US domestic part of the international call will be the same carrier that brings the call across the Atlantic. In order for each carrier to provide international service (AT&T, MCI, etc.) that carrier has to reach an agreement with a carrier at the other end. AT&T, MCI, etc. have each reached agreements with BTI for bringing traffic into and out of the U.K. If BT chooses an MCI circuit for the transatlantic portion of the call, it will remain on MCI for the domestic portion. I suspect, but am not sure, that BT just uses a percentage split, where the percentage of outgoing traffic offered to each carrier is the same as the percentage of incoming traffic received from that carrier. /john [Moderator's Note: Do you know whether or not the British Telecom subscriber gets any choice in the matter? That is, can they indicate by any routing code, or by going through an operator that they wish the call to be routed over AT&T or over MCI? If a subscriber makes a collect call to the USA for example, does whoever pays for the call get to select the international carrier? Or are they stuck with whoever BT routes them on? PT]