Subject: RE: [Ieprep] overall issues and REQ-11 thru REQ-15

From: "Gunn, Janet" <[email-masked]>
Date: Thu, 10 Oct 2002 16:34:20 -0400

-----Original Message-----
From: Henning Schulzrinne [mailto:[email-masked]]
Sent: Thursday, October 10, 2002 4:29 PM
To: Gunn, Janet
Cc: King, Kimberly S.; Ieprep (E-mail)
Subject: Re: [Ieprep] overall issues and REQ-11 thru REQ-15

> [JPG] The gateway needs to recognize 710 as a valid prefix, and know what
to
> do with it (at a minimum route it to something that knows what to REALLY
do
> with it, such as one of the 3 GETS IXCs, or a GETS capable LEC).

Not necessarily. In many (smaller network) cases, the gateways are about 
as smart or dumb as a PBX, i.e., they just talk to a local PSTN switch. 

[JPG] That is the problem.  Some PBXs are so dumb that they don't recognize
710 as a valid "area code", and drop the call.  We would prefer to avoid
that situation in the IP gateway.  I agree that a carrier may have to do the
routing- but the gateway has to be willing to pass it to the carrier.

A carrier will likely have to do the routing, as you mention; the 
gateway effectively acts like a local telephone switch with rather 
peculiar line interfaces or a tandem with an IP trunk interface. In both 
cases, this is invisible to the IP side. Since we don't specify boxes, I 
don't think we need to worry about this.

> [JPG] Even if there is no direct relationship between the user and the
> gateway, there needs to be an indirect relationship, e.g., the user has a
> relationship with a database or other auth* agent, and the gateway also
has
> a relationship with the database or auth* agent.

Yes, typically the gateway won't do the authentication itself, 
particularly if its of the MGCP-kind. The associated SIP UA will do 
this. In that case, SIP ends on the UA, so the gateway is just a remote 
"extension" of the SIP UA.

...

> [JPG] Some of the (future) variants of GETS use the instrument or line
> identification as part of the auth* process, and may auth* somewhere other
> than the IXC.  So it needs to be more general.

In VoIP, I don't see how "line identification" can be useful (or even 
what this should mean).

[JPG] Maybe the IP address or URI?
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From: Henning Schulzrinne <[email-masked]>
Date: Thu, 10 Oct 2002 16:39:05 -0400

> routing- but the gateway has to be willing to pass it to the carrier.

You will have corporate-style gateways (even if they are located on the 
premises of a three-letter agency), so both cases will occur.

> [JPG] Maybe the IP address or URI?

The URI identifies the user and maybe some random host name. The IP 
address often varies from call to call and is furthermore trivially 
spoofed, at least within the same network. Thus, I don't think that this 
is something we should recommend. It serves no purpose that I can 
discern. Why would I care which IP address originated the request?