Subject: RE: [AAA-WG]: Issue 123: Use of Application Identifiers in routing

From: "Sreemanthula Srinivas (NRC/Dallas)" <[email-masked]>
Date: Mon, 27 Aug 2001 18:03:33 -0500

Sorry, the mail was accidentally sent before I completed it. Here is the
rest.

>On Mon, Aug 27, 2001 at 04:23:09PM -0500, Sreemanthula Srinivas
(NRC/Dallas) wrote:
>> Pat, thanks for the reply.  But, I feel that the "gateway" nodes are
>> more than likely proxy nodes that are located on the edge of a
network
>> (realm).
>
>Just want to make sure that you understand that the use of the term
proxy
>node implies specific functionality. If you are not aware of that, I
would
>urge you to read section 2.9.2 in the base spec (but if you are in fact
>talking about a proxy, then ignore my comment).

I see that they can enforce routing, roaming and other policies, 
hence they are proxies.

>> All the messages for this realm will arrive at this gateway
>> node based on realm based routing.  They may have the knowledge of
>> specific AAA servers within its realm supporting specific
applications
>> (MIP, NASREQ etc.) and perform the routing using the application
>> identifier information.

>Right, and the reason your network would work this way is because the
"gateway"
>advertises itself as a relay (advertises all applications), so it is
guaranteed
>to receive all requests destined for the local realm. The "gateway"
then
>forwards the message to the appropriate internal server, based on the
>application.

>This is exactly the way the base spec is written.

My understanding is that only Relay and redirect agents use the "Relay"
application
id while others must specifically advertise the supported identifiers.

>>  The point, which not clear from the existing
>> text, is that the use of application identifiers is not a MUST (or
>> required as in the text) but there are cases where it is useful and
>> therefore a "MAY".

>Your above sentence unfortunately confuses me. Are you stating that the
>routing using appl-id is NOT a MUST in the current spec, or that it is
>and you want it softened? If the former, then it needs to be fixed, if 
>the latter, please provide why the above example, using the existing
text,
>doesn't work for you.

Ok, it is the latter. The use of application id in routing need only be
optional.
We are insisting on the realm based routing, because this guarantees
that any diameter
message will arrive at the destination network irrespective of the
capabilities supported
in the intermediary network.  We do not want the message to be rejected
because some 
broker is not able to support the application.  This may be more of an
issue as new applications come in action. For two networks A and B
supporting a new application id, there is no 
need for intermediary network to be upgraded.

Thanks,
Srini

>Thanks,

>PatC

---

From: Pat Calhoun <[email-masked]>
Date: Mon, 27 Aug 2001 15:53:58 -0700

> need for intermediary network to be upgraded.

If it is a proxy, then by its very definition, the intermediary network
MUST be upgraded. A proxy is a intermediate device that understands specific
applications, and makes policy changes to request and/or answer messages.
In order to make such changes, it must be upgraded to support future 
applications.

It really sounds like you want a relay, and not a proxy.

PatC