All,
Good point, Pete! It's a shame you weren't on the call (there was a certain amount of guesswork as to how 800 numbers work)!
There are two ways of handling this that I can see immediately. Although philosophically different, in practice they will normally amount to the same thing: 1. The "owner" of a domain needs to be told where a query originates, given that the calling location may affect the answer it gives or: 2. A border element handling queries for 800-type numbers needs to know what to do with it depending on the origin of the query.
Regards, Chris ---------------------------------------- Dr Chris Purvis - Senior Development Engineer, WAVE CC Software Madge Networks Ltd, Wexham Springs, Framewood Road, Wexham, Berks. Phone:+44 1753 661359 email: cpurvis@madge.com
-------------------------------- Dear All,
It may not be possible to handle 800 numbers in the same way as other numbers as the destination may be based on the geographical location of the caller. For example, ISPs may be accessible by something like an 800 number which may be fixed for a whole country, but the POP you end up connected to may vary depending on where you called from.
I'm not sure what the implications of this are, but it is something to think about!!!
Regards,
Pete ================================= Pete Cordell BT Labs E-Mail: pete.cordell@bt-sys.bt.co.uk Tel: +44 1473 646436 Fax: +44 1473 645499 =================================
From: Chris Purvis WVdevmt-WS[SMTP:cpurvis@MADGE.COM] Sent: 02 September 1998 13:09 To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: H.323 Addresses
Radhika,
We are discussing about H.323 addresing schemes in our bi-weekly H.323 inter-GK conf calls.
The H.323 addresses that are being considered are 1. E.164, 2. E-mail,
URL, and 4. TCP/UDP/RTP port addresses (and 5. aliases as well I
guess).
Although a hierarchical notion of addressing scehmes have been
discussed, we
have also recognized that some other variations of addressing schemes
are
there.
For example, people change their physical locations, but they might
have
to
keep the same E.164 addresses. So, a translation is needed. Therefore,
the
very physical relationship of E.164 addressing scheme (e.g., knowing
NPAs
and NXXs, one can find the distance) has been broken.
I was under the impression that finally (after several weeks of discussion) we'd reached closure on this in last Thursday's call. The solution that I understood had been agreed came in two parts:
- Mobile IP solves most of the problem for us - E.164 number resolves
to an IP address which may be anywhere in the world at any given moment in time. 2. If a user wants to move (and take their number with them) to being in an administrative domain with an otherwise reasonably contiguous E.164 address space, this is easily handled as follows. The domain that "should" (in the hierarchical sense) "own" the number that the user is keeping holds a record of where to contact the current holder of that number (which will typically be an entity to which an LRQ message can be sent).
Another example can be 800 numbers where the translation is also
needed.
It seemed to be agreed in the call that 800 numbers are not a special case, but merely an example of number portability.
In addition, from mobility point of view (device or person) wired (and wireless?) environement may also be looked into.
Does this mean anything at all?
As we go froward, we may consider many of those aspects as pointed
above
to
provide solutions for the H.323 addressing schemes.
I was under the impression that we'd reached closure on most of these already.
Regards Chris
Dr Chris Purvis - Senior Development Engineer, WAVE CC Software Madge Networks Ltd, Wexham Springs, Framewood Road, Wexham, Berks. Phone:+44 1753 661359 email: cpurvis@madge.com
Hi All,
It's a shame I wasn't on the call, I might find out what's going on :-( Thanks to those who are exposing it on the list. :-)
In my mind, address resolution (or number translation) is a multistage process.
In the context of the caller, a destination address may be an "internal" form like an abbreviated dialing number (*21), a service prefixed number (01161294332374), or a nickname ("doug"), that has to be translated into an "external" form. The result of this stage is an external address.
Once in the external form that identifies the callee, the number is subject to resolution in the context of the callee. I think that 800 numbers are like this. Since geographical information is probably not known about the source or the destination, much less path metrics between them, factoring that into the resolution may be a problem. The result of this stage is an effective address.
If the response is a prioritised sequence of endpoints, then the source can select from the endpoints within each priority based on characteristics. For example 1-800-555-1212 => (1-415-555-1212, 1-212-555-1212) and I can select my area code if I know it.
The third step involves endpoint location, sometimes called gateway location. This involves taking the effective address and locating a physical (transport) address that can handle it. This could also be a prioritised sequence of endpoints (gateways), for each effective address. The source can then select from the endpoints within each priority based on characteristics. I might look in my IP routing tables, ping them or use RSVP.
I don't think that "geographical" proximity is the *real* determining factor here. It doesn't matter if the source is sitting on top of the destination if the link is a 300 baud serial line.
I think that the problem being canvased here is one that comes from the PSTN domain where the 800 charges are distance dependent. I don't think that it translates directly to the packet network domain, where charges are often distance independent.
What's more likely to be interesting, is the moving call centre where the effective address follows the sun from London to San Francisco to Sydney to maximise daytime staff utilisation. Here your 1-800 number will translate to 44-171, 1-415, and 61-2 depending on the time of day.
Regards,
Douglas
At 18:01 02/09/98 +0100, Chris wrote:
All,
Good point, Pete! It's a shame you weren't on the call (there was a certain amount of guesswork as to how 800 numbers work)!
There are two ways of handling this that I can see immediately. Although philosophically different, in practice they will normally amount to the same thing:
- The "owner" of a domain needs to be told where a query originates,
given that the calling location may affect the answer it gives or: 2. A border element handling queries for 800-type numbers needs to know what to do with it depending on the origin of the query.
Regards, Chris
Dr Chris Purvis - Senior Development Engineer, WAVE CC Software Madge Networks Ltd, Wexham Springs, Framewood Road, Wexham, Berks. Phone:+44 1753 661359 email: cpurvis@madge.com
Dear All,
It may not be possible to handle 800 numbers in the same way as other numbers as the destination may be based on the geographical location of the caller. For example, ISPs may be accessible by something like an 800 number which may be fixed for a whole country, but the POP you end up connected to may vary depending on where you called from.
I'm not sure what the implications of this are, but it is something to think about!!!
Regards,
Pete
Pete Cordell BT Labs E-Mail: pete.cordell@bt-sys.bt.co.uk Tel: +44 1473 646436 Fax: +44 1473 645499 =================================
From: Chris Purvis WVdevmt-WS[SMTP:cpurvis@MADGE.COM] Sent: 02 September 1998 13:09 To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: H.323 Addresses
Radhika,
We are discussing about H.323 addresing schemes in our bi-weekly H.323 inter-GK conf calls.
The H.323 addresses that are being considered are 1. E.164, 2. E-mail,
URL, and 4. TCP/UDP/RTP port addresses (and 5. aliases as well I
guess).
Although a hierarchical notion of addressing scehmes have been
discussed, we
have also recognized that some other variations of addressing schemes
are
there.
For example, people change their physical locations, but they might
have
to
keep the same E.164 addresses. So, a translation is needed. Therefore,
the
very physical relationship of E.164 addressing scheme (e.g., knowing
NPAs
and NXXs, one can find the distance) has been broken.
I was under the impression that finally (after several weeks of discussion) we'd reached closure on this in last Thursday's call. The solution that I understood had been agreed came in two parts:
- Mobile IP solves most of the problem for us - E.164 number resolves
to an IP address which may be anywhere in the world at any given moment in time. 2. If a user wants to move (and take their number with them) to being in an administrative domain with an otherwise reasonably contiguous E.164 address space, this is easily handled as follows. The domain that "should" (in the hierarchical sense) "own" the number that the user is keeping holds a record of where to contact the current holder of that number (which will typically be an entity to which an LRQ message can be sent).
Another example can be 800 numbers where the translation is also
needed.
It seemed to be agreed in the call that 800 numbers are not a special case, but merely an example of number portability.
In addition, from mobility point of view (device or person) wired (and wireless?) environement may also be looked into.
Does this mean anything at all?
As we go froward, we may consider many of those aspects as pointed
above
to
provide solutions for the H.323 addressing schemes.
I was under the impression that we'd reached closure on most of these already.
Regards Chris
Dr Chris Purvis - Senior Development Engineer, WAVE CC Software Madge Networks Ltd, Wexham Springs, Framewood Road, Wexham, Berks. Phone:+44 1753 661359 email: cpurvis@madge.com
participants (2)
-
Chris Purvis WVdevmt-WS -
Douglas Clowes