Subject: RE: [Sipping] draft-yu-tel-url-04.txt comment

From: "Yu, James" <[email-masked]>
Date: Thu, 18 Apr 2002 10:15:29 -0500

> 
> So, what you say is: if user=phone, an implementation must 
> always be able to
> handle parameters in the SIP-URL???
> 
> If this is the case, I think it must be specified in bis, 
> since user=phone is
> also specified there.
> 
> OR, we can say that an implementation not supporting the 
> parameters will simply
> treat the whole user part as a single string, but again - 
> that would probably be
> rejected by PSTN routing handlers etc.
> 

The user part can be treated as a single string first.  There is no need to
understand or process the user part if the received sip URL in the
Request-URI contains a host that is not the node itself.  Based on the
routing precedence, this node is supposed to route based on the host
information.  Only when this node is that host, it needs to process the user
part.  In that situation, when "user=phone" is present, it knows that a
telephone number is in the user part and other tel URL parameters may be
present.  If this node does not understand some of the parameters in the
user part, it can ignore them.  The actual message parsing and processing is
certainly much more complicated.

James

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---

From: Christer Holmberg <[email-masked]>
Date: Fri, 19 Apr 2002 07:57:04 +0300

Hi,

> part.

That is true, but the intermediate node may still change the Request-URI. In
that case it could remote the old user part - INCLUDING your parameters - and
add a new user part without them. I guess you don't want that to happend, do
you?

> In that situation, when "user=phone" is present, it knows that a
> present.

Again, that's NOT how it's said in bis. Since "user=phone" is defined in bis, if
it requires some special treatment of the URL user part I think it also must be
defined in bis.

> If this node does not understand some of the parameters in the user part, it
> can ignore them.

Yes, yes, yes. But, again, my bis compliant implementation doesn't even know
there are any parameters to ignore in the first place, since bis doesn't specify
any parameter for the user part - no matter if "user=phone". It will assume the
WHOLE user part represents the user, eg a phone number, or whatever.

Others have asked, and I also still would like to know, why you can't define the
parameters as uri-parameters instead??? Maybe there is a good reason, and maybe
there is something I've missed, so please tell me.

Regards,

Christer Holmberg
Ericsson Finland