Subject: Re: [Ecrit] Proposed requirement: split responsibility

From: Andrew Newton <[email-masked]>
Date: Mon, 23 May 2005 13:52:24 -0400

On May 23, 2005, at 1:28 PM, Brian Rosen wrote:

> Your example however is illustrative of how the NENA i2 mechanism 
> works on
> civic boundaries.  It assigns state/county/city areas to a specific 
> part of
> the database.  There is a "root server", which, when queried, returns 
> a list
> of servers that have data for a specified city/county/state.  Where the
> boundary doesn't exactly match the city/county/state boundary, you get 
> more
> than one server in the response.  Each of the servers can forward the
> request to the actual server, if it knows.
>
> I don't like this mechanism as much as the DNS proposal I have made, 
> which
> always gets the query to the authoritative server with one request by 
> the
> client, but it works.

Isn't this making an assumption that all such splits occur on the civil 
address boundaries?  While I believe there are situations where such 
divisions are made based on artificial criteria such as streets marked 
"North" vs streets marked "South", it seems more reasonable that such 
things are based on major geographic features (a river that bisects a 
city), some artifact of location based on telco COs, the need of the 
population centers (more crime-ridden sections of a city probably 
require a greater number of resources), etc...

-andy

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From: "Brian Rosen" <[email-masked]>
Date: Mon, 23 May 2005 14:08:49 -0400

I'd hate to generalize beyond North America.  Here, the boundary is defined
in both civic and geo forms, regardless of what the boundary is chosen to
be.  The base form up to cell phone days was civic.  They added polygons for
mobile phone routing.  Today, we have both; a precise civic and a precise
geo.  "Precise" is in the eyes of the beholder of course.

It's not exactly easy, but given any street address, we can tell you which
PSAP gets the call.

It's a little more complex for geo, because, in North America, routing for
cell phones is different in some areas than routing for wireline.  There
exists a complete set of polygons for mobile routing, and I am told that one
firm has a complete, or nearly complete set of polygons for wireline geo
routing. 

I suspect that in other countries that have more than one PSAP that gets the
call, there are precise civic routing mechanisms, albeit they may be pretty
historically derived, rather than having any boundary you might choose
today.  Nevertheless, in the cases I know, again allowing for some pretty
arcane ways to get at the data, the actual boundaries are defined by civic
addresses.  There may be polygons available, but I know that there are
differences in wireless and wireline routing in other countries too.

Brian

> -----Original Message-----
> From: Andrew Newton [mailto:[email-masked]]
> Sent: Monday, May 23, 2005 1:52 PM
> To: Brian Rosen
> Cc: [email-masked]; 'Ted Hardie'; 'Henning Schulzrinne'
> Subject: Re: [Ecrit] Proposed requirement: split responsibility
> 
>