Subject: Re: [Ieprep] Re:

From: [email-masked]
Date: Thu, 23 May 2002 10:07:23 EDT

In a message dated 5/22/02 4:21:03 PM Eastern Daylight Time, 
[email-masked] writes:

> The term "the public network of a country" makes sense in the straight 
> telephony world, but I am not sure it makes sense in the IP world.
> 
Yes, I understand that this is a fundamental change in concept for voice over 
IP, SIP, or using the Internet as the infrastructure for a public "telephone" 
service. But it seems also that this concept is completely contradictory to 
the concept of an Emergency Service for which certain individuals are given 
authority to do something (get precedence) by a government agency. We seem to 
be at a point where these two concepts are coming against each other.

I suspect that the concept I intended, and that I think is needed, would be 
better expressed as "the public telephone service of a country" which somehow 
runs on "the global network".

If there really is one "global network" for public "telephone" service, then 
we would have two choices for Resource-priority header:
1. Define one worldwide applicable namespace that includes everything 
everyone wants (impossible?)
2. Each country or region defines a namespace for use for service for that 
country or region. This might also need lots of definition of interworking 
betwen countries, how to handle namespace and value you don't understand, 
etc. since all these regions need to interwork.

I suppose this is one of those areas where the service concepts developed for 
the current well-structured telephony network may not work on the 
less-structured IP network.

Mike

---

From: Henning Schulzrinne <[email-masked]>
Date: Thu, 23 May 2002 10:43:54 -0400

The crucial part here is authentication and authorization. Just having a 
name that's recognized by the remote end is not the difficult or 
important part - the remote end has to be able to verify that the 
session setup message is indeed authorized to use that label.

Thus, the likely limitation to scaling isn't going to be agreeing on 
labels, but a "roaming" authentication infrastructure.

We have two cases:

- The call originates on the PSTN, traverses an IP cloud and then lands 
at another gateway. If the terminating gateway provider trusts the 
originating gateway, priority mechanisms can be activated. Unless the 
number of schemes is counted in the dozens, keeping a table that maps a 
few different namespaces is not going to be hard, as long as the lists 
don't change on a monthly basis. I see no reason why they should; 
government bureaucracy acts as a natural braking agent here that limits 
the rate of change.

- The call originates on an IP phone and reaches a PSTN gateway, 
possibly and probably through a proxy. The message needs to be properly 
authenticated, either by the originator or using some kind of 
third-party authentication as is being discussed in the SIP WG. Again, 
the likely scaling limit is the cross-domain authentication, not the 
size of a table.

For the latter case, I suspect that we'll get something similar to 
today, where only certain carriers support GETS, say. If you happen to 
be on a payphone operated by "COCOTS rip-off & swindle LD disservice", 
you will have to get to the established carriers that know about you and 
your privileges by dialing their 1010 carrier code or 800 number. In the 
case of an IP phone, this will likely mean the use of the Yu draft 
("cic") combined with a tel URL.

In summary, I think the notion of a global telephone system is a 
distraction. It doesn't exist today, as far as priority treatment is 
concerned.

[email-masked] wrote:
> Yes, I understand that this is a fundamental change in concept for voice 
> over IP, SIP, or using the Internet as the infrastructure for a public 
> "telephone" service. But it seems also that this concept is completely 
> contradictory to the concept of an Emergency Service for which certain 
> individuals are given authority to do something (get precedence) by a 
> government agency. We seem to be at a point where these two concepts are 
> coming against each other.
> 
> I suspect that the concept I intended, and that I think is needed, would 
> be better expressed as "the public telephone service of a country" which 
> somehow runs on "the global network".
> 
> If there really is one "global network" for public "telephone" service, 
> then we would have two choices for Resource-priority header:
> 2. Each country or region defines a namespace for use for service for 
> that country or region. This might also need lots of definition of 
> interworking betwen countries, how to handle namespace and value you 
> don't understand, etc. since all these regions need to interwork.
> 
> I suppose this is one of those areas where the service concepts 
> developed for the current well-structured telephony network may not work 
> on the less-structured IP network.
> 
> Mike
> 

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