grayt@uunet.uu.net> (06/12/90)
In article <8733@accuvax.nwu.edu> John Slater <johns@happy.uk. sun.com> writes: X-Telecom-Digest: Volume 10, Issue 418, Message 6 of 10 >>In a perfect world I could dial "+44 81 676 XXXX" to reach my number >>in London from *anywhere* in the world, including the UK (where + >>means 010). Similarly it would be nice to be able to dial 011 1 415 >>XXX XXXX to reach San Francisco from anywhere in the US. >>I was originally going to post this with lots of ":-)", but seriously >>though folks, why should it be difficult with modern switches? The main problem with this proposal would be the size of the data base required inside of each switch. Think of the routing problems which would occur when any digit sequence could be used to identify a trunk route. Each switch would be required to maintain the telephone number of all of the subscribers in the world. Even small CDO's would require gigabytes of disk storage. In the SS7 network, translations of 800 numbers is done at a central point called the SCP. This could provide a unique service which could provide a lucrativve source of income for service providers. Instead of vanity licence plates, subscribers could buy vanity telephone numbers. Think of it, vanity numbers could be preceded by a distinguishing code. BE the first one to get a naughty word past the telco censors.
johns@happy.uk.sun.com (John Slater) (06/15/90)
In article <8869@accuvax.nwu.edu>, mitel!spock!grayt@uunet.uu.net (Tom Gray) writes: >In article <8733@accuvax.nwu.edu> John Slater <johns@happy.uk. >sun.com> writes: >X-Telecom-Digest: Volume 10, Issue 418, Message 6 of 10 >>>In a perfect world I could dial "+44 81 676 XXXX" to reach my number >>>in London from *anywhere* in the world, including the UK (where + >>>means 010). Similarly it would be nice to be able to dial 011 1 415 >>>XXX XXXX to reach San Francisco from anywhere in the US. >>>I was originally going to post this with lots of ":-)", but seriously >>>though folks, why should it be difficult with modern switches? >The main problem with this proposal would be the size of the data base >required inside of each switch. Think of the routing problems which >would occur when any digit sequence could be used to identify a trunk >route. Each switch would be required to maintain the telephone number >of all of the subscribers in the world. Even small CDO's would require >gigabytes of disk storage. I don't see why this is the case. Surely all the switch needs to know is its own country and area codes. Here's an example. Suppose I dial my home number as 010 44 81 676 0694 from a payphone down the street. As soon as it gets the second 4, the switch thinks "Ah - 01044 means a call to the UK. But I'm in the UK, so I'll pretend the caller dialled 0 instead. Now we've got 081-676 XXXX. But I'm in the 081 area, so I'll pretend the caller didn't dial the code. (This bit already works - I can dial 081-676 XXXX from said payphone) So what he/she really wants is 676 XXXX". All other country codes and area codes get passed on as normal. All the switch has to do is delay passing control onto an international switch until it has received sufficient digits to check that the call really needs it. Why should it be any more complicated than that? John Slater Sun Microsystems UK, Gatwick office
hwt@uunet.uu.net (Henry Troup) (06/15/90)
In article <8958@accuvax.nwu.edu> "John Slater <johns@happy.uk. sun.com> writes: >All the switch has to do is delay passing control onto an >international switch until it has received sufficient digits to check >that the call really needs it. Why should it be any more complicated >than that? Eventually, it shouldn't be more complicated than that. However, as late as last August, some parts of the U.K. still had routing codes, not area codes. A routing code is a 'context-dependent' code: the London routing code for Dundee, Scotland is 382. The London routing code for St. Andrews is 396 (?). But you dial a totally different code to call St. Andrews from Dundee. The Tayside Region phone book has an amazing number of tables of what to dial from _where_you_are_ to _where_you_want_to_call. I assume that this means the Scottish switches are old crossbar and SxS, with no smarts soever to translate anything. Henry Troup - BNR owns but does not share my opinions ..uunet!bnrgate!hwt%bwdlh490 or HWT@BNR.CA