Subject: RE: [Ecrit] Issue 30: Summary

From: "Michael Hammer \(mhammer\)" <[email-masked]>
Date: Mon, 23 Jan 2006 09:17:04 -0500

Not necessarily an issue, but I need to be able to correctly parse the
sentence.

Mike

> -----Original Message-----
> From: Clive D.W. Feather [mailto:[email-masked]] 
> Sent: Monday, January 23, 2006 9:11 AM
> To: Michael Hammer (mhammer)
> Cc: Hannes Tschofenig; Raymond Forbes; 
> [email-masked]; [email-masked]
> Subject: Re: [Ecrit] Issue 30: Summary
> 
> Michael Hammer (mhammer) said:
> > When you talk about "emergency numbers", are you referring 
> to an E.164 
> > number that the "emergency dial string" gets translated to?
> 
> And what if there isn't such a thing?
> 
> -- 
> Clive D.W. Feather  | Work:  <[email-masked]>   | Tel:    
> +44 20 8495 6138
> Internet Expert     | Home:  <[email-masked]>  | Fax:    
> +44 870 051 9937
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> 

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From: "Clive D.W. Feather" <[email-masked]>
Date: Mon, 23 Jan 2006 16:47:10 +0000

> > And what if there isn't such a thing?

What if the "emergency dial string" is not translated to an E.164 number,
but is simply routed directly through the network?

-- 
Clive D.W. Feather  | Work:  <[email-masked]>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <[email-masked]>  | Fax:    +44 870 051 9937
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---

From: "Brian Rosen" <[email-masked]>
Date: Mon, 23 Jan 2006 11:53:53 -0500

"Routed through the network"?  Few systems do this, but ones where the only
emergency number is an E.164 do.

In our work, we interpret an emergency dialstring within a dial plan to the
universal emergency identifier.  Then we map that, using the mechanisms we
are discussing here in ecrit, to some routable URI, be it a tel URI routed
as any other tel URI would, a SIP URI, routed as any other SIP URI would,
etc.

If in some location, mapping yields an e.164 in a tel uri, then we would
route it appropriately, perhaps using an enum dip, ...

Brian

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
Clive D.W. Feather
Sent: Monday, January 23, 2006 11:47 AM
To: Michael Hammer (mhammer)
Cc: [email-masked]
Subject: Re: [Ecrit] Issue 30: Summary

---

From: "Clive D.W. Feather" <[email-masked]>
Date: Mon, 23 Jan 2006 17:35:14 +0000

> as any other tel URI would, a SIP URI, routed as any other SIP URI would,

We seem to be at cross-purposes.

Someone seemed to be suggesting that any diallable (in the PSTN) emergency
number mapped to an E.164 number, so enum systems could look up the latter.
The only point I was trying to make is that in some countries there *is* no
such E.164 number. E.g. in the UK "999" (on landlines, at least) is handled
by special routeing in the telephone network, not by mapping it to an E.164
number.

---

From: Andrew Newton <[email-masked]>
Date: Mon, 23 Jan 2006 14:26:16 -0500

> We seem to be at cross-purposes.

No, we seem to have wondered into the weeds.

I thought the issue here was: either the UA or some proxy needs to  
convert an emergency dialstring to a universal identifier (perhaps  
Henning's URN proposal) before making an LCMS query.  The emergency  
dialstring comes in two varieties: "home" and "visited".  Home  
emergency dialstrings can be preconfigured (details vary, but not  
necessarily important to this conversation).  Visited emergency  
dialstrings are problematic as there needs to be a way to get them  
into the said UA or proxy.

I was not under the impression that this requirement was about  
universal dialstrings, be they E.164 numbers or not.

-andy

---

From: "Brian Rosen" <[email-masked]>
Date: Mon, 23 Jan 2006 14:38:30 -0500

I don't think we are at cross purposes, although I do think we are
misunderstanding each other.

SOME countries don't have emergency numbers; you must dial an e.164 to get
help.  Often, there is more than one (police, fire, ems, ...)

SOME countries have emergency numbers.  AFAIK, every one who does has
special routing for them in the PSTN.

In ecrit, we FIRST expect dial plan interpretation to translate the
dialstring for the location where the caller is calling from to a universal
emergency identifier.  Where there is only one emergency number, that would
be urn:service:sos.  Where there is more than one, that would be e.g.
urn:service:sos.police. That would get all emergency calls having the same
URI regardless of where they are calling from.  

THEN we can use common (that is, country independent) routing mechanisms to
route emergency calls to an entity that can determine the correct PSAP for
that call.  

THEN, we use the ecrit mapping mechanism to translate location to the URI of
the PSAP.

THEN, when we have a URI of the PSAP, we route that.  It may be an e.164 in
a tel: uri, in which case we would use PSTN routing.  That may involve an
enum dip.  It may be a sip uri which we would route with a DNS lookup and a
normal SIP route method.

Brian

---

From: "Raymond Forbes" <[email-masked]>
Date: Tue, 24 Jan 2006 10:12:03 +0000

Clive,

I am not aware that the IETF is interested in UK PSTN Routeing (999, 112 
or otherwise)

911 is not supported in the UK, 911345 may be a local number, national 
dialling is not required. If you dial 911 in the UK it will respond with 
n/u tone as the 6 or 7 digit local number must be dialling in one sequence 
and mapped by the local exchange.

Regards,

Ray Forbes.

+44 24 7656 3106 phone
+44 24 7656 3816 fax.
+44 771 851 1361 Mobile/text
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"Clive D.W. Feather" <[email-masked]>
Sent by: [email-masked]
23/01/2006 17:35
 
        To:     Brian Rosen <[email-masked]>
        cc:     [email-masked]
        Subject:        Re: [Ecrit] Issue 30: Summary

Someone seemed to be suggesting that any diallable (in the PSTN) emergency
number mapped to an E.164 number, so enum systems could look up the 
latter.
The only point I was trying to make is that in some countries there *is* 
no
such E.164 number. E.g. in the UK "999" (on landlines, at least) is 
handled
by special routeing in the telephone network, not by mapping it to an 
E.164
number.

-- 
Clive D.W. Feather  | Work:  <[email-masked]>   | Tel:    +44 20 8495 
6138
Internet Expert     | Home:  <[email-masked]>  | Fax:    +44 870 051 
9937
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
Thus plc            |                            |

---

From: "Clive D.W. Feather" <[email-masked]>
Date: Tue, 24 Jan 2006 10:15:03 +0000

> I am not aware that the IETF is interested in UK PSTN Routeing (999, 112 

It isn't. However, it is interested in PSTN numbering where that interacts
with ecrit, enum, and so on.

> 911 is not supported in the UK,

Correct.

> 911345 may be a local number, national 
> dialling is not required.

As I said, there are about 30 locations where this is the case.

> If you dial 911 in the UK it will respond with 

Not so. While there is a timeout, my local exchange (I've just tested it)
will accept a more than 10 second gap between digits.

It so happens that, if I dial 911 here, I get an announcement immediately
after the second 1. I get the same announcement if I dial 912 or 753,
because none are valid prefixes. If, however, I'm in one of those 30 areas
I would expect to get silence after dialling 911 until the timeout expires.