Re: Progression of draft-polk-sip-rph-in-responses-00

Jeroen van Bemmel <jbemmelzonnet.nl&gt; wrote
on 09/21/2007 03:19:09 PM:

&gt; Tim, Brian,

&gt; 

> First of all a question to clarify the requirements further: is it

>; possible/valid for the request to have no specific priority while
its 

> response does, or should the RPH headers in a response always be the

&gt; same or a subset of those in the request (i.e. copied)? I assume the
latter

>
No, not a valid assumption.  
In order to support legacy applications, priority
markings (e.g. RPH) may be set based on the "dialed number&quot;-
e.g., by parsing the Request URI.
In some architectures (e.g. IMS) there may be RPH-capable
SIP actors  (Type A) which do not parse the Request URI looking for
the key strings.  Such a SIP actor would send a SIP Invite WITHOUT
RPH.  However, a subsequent  RPH-capable SIP actor (which DOES
parse the Request URI looking for the key strings) (Type B) would set RPH,
both in Invites sent forward, and in responses sent back.
So the "Type A" SIP actor could send out
an Invite without RPH, but get back a response WITH RPH.
I have oversimplified, but the point is that it is
not a valid assumption.
Janet 

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Janet P Gunn wrote:
> Jeroen van Bemmel <jbemmelzonnet.nl> wrote on
09/21/2007 03:19:09 PM:
> 
>> Tim, Brian,
>>
>> First of all a question to clarify the requirements
further: is it 
>> possible/valid for the request to have no specific
priority while its 
>> response does, or should the RPH headers in a
response always be the 
>> same or a subset of those in the request (i.e.
copied)? I assume the 
> latter
> No, not a valid assumption. 
> 
> In order to support legacy applications, priority
markings (e.g. RPH) may 
> be set based on the "dialed number"- e.g., by
parsing the Request URI.
> 
> In some architectures (e.g. IMS) there may be
RPH-capable SIP actors (Type 
> A) which do not parse the Request URI looking for the
key strings.  Such a 
> SIP actor would send a SIP Invite WITHOUT RPH. 
However, a subsequent 
> RPH-capable SIP actor (which DOES parse the Request URI
looking for the 
> key strings) (Type B) would set RPH, both in Invites
sent forward, and in 
> responses sent back.
> 
> So the "Type A" SIP actor could send out an
Invite without RPH, but get 
> back a response WITH RPH.
> 
> I have oversimplified, but the point is that it is not
a valid assumption.
>

Ok, so what keeps me as a Joe End User from putting a
"higher priority
than the president" marking on every response I send?
You can't
challenge a response or send me an error code if you don't
like my
priority. Does every response require authentication of
priority level?

Do we also have a new requirement for a node to
"learn" the priority
level of a dialog from a response, and then include that
priority level
in future requests on that dialog?

It seems like this mechanism could be used to "jack
up" the priority
level of a dialog:

1) Alice sends a low priority request to Bob.
2) Bob replies with a high-priority marking in the
response.
3) Alice marks all future requests and responses in this
dialog high
priority.

--
Dean

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Re: Progression of draft-polk-sip-rph-in-responses-00

Thread: Re: Progression of draft-polk-sip-rph-in-responses-00